1. Introduction
2. The Legal Framework
         2.1     The legal scope of application of the CISG
         2.2     The validity exception in Art. 4 CISG
         2.3     Consequences for Standard Terms in a CISG Contract
3. The Incorporation of Standard Terms
         3.1     The general principles
         3.2     Making the terms "available" or "mere reference"?
         3.3     The language issue
         3.4     The battle of the forms
4. The Material Validity of Standard Terms
5. Instead of a Conclusion: What Lies Ahead?

1. INTRODUCTION

Sales contracts, both domestic and international, are often concluded on the basis of standard terms, which are introduced by one of the parties and have not been the subject of individual negotiations. The use of standard terms raises a number of issues which have led to controversial debate in domestic legal systems. By contrast, the United Nations Convention on Contracts for the International Sale of Goods (hereinafter 'CISG' or 'Convention') does not provide specific rules for the use of standard terms. Nonetheless, this does not mean that the issue will be left to the applicable domestic law. In fact, some of the legal issues that can arise with regard to standard terms are widely regarded as being governed by the Convention, as has been pointed out by Peter Schlechtriem on various occasions.[1] Opinions are divided regarding the details, and the issues are far from being settled. This is why the issue of standard terms despite not being a brand new phenomenon, is still on the CISG horizon for future work. This paper does not attempt to give a complete overview of the different approaches that have been suggested or of the problems that can arise. It aims to initiate debate on selected issues as to whether one should take steps to find harmonised solutions for them. [page 123]

2. THE LEGAL FRAMEWORK

The first sentence of this provision defines the legal scope of application of the CISG positively by stipulating that it governs the formation of the contract and the rights and obligations of the parties. It is submitted as a general rule that the terms 'formation' and 'rights and obligations of the parties' should be understood as covering everything that the Convention actually addresses in Arts. 11-13, 14-24 CISG ('formation') and Arts. 25-88 CISG ('rights and obligations of the parties').[2]

By contrast, the CISG does not cover those issues which neither belong to 'formation' nor to the 'rights and obligations of the parties'. By way of example and without being exhaustive,[3] the second sentence of Art. 4 CISG names two areas which are not governed by the Convention, amongst them issues of validity.

2.2 The validity exception in Art. 4 CISG

The validity exception in Art. 4 CISG has given rise to considerable amount of debate among scholars and courts.[4] It is submitted that the provision should be given an autonomous interpretation (Art. 7(1) CISG),[5] so that the term 'validity' does not [page 124] simply mean what (the applicable) domestic law says, rather it has to be interpreted against the background of the CISG.

In doing so, the validity exception must be brought in line with the positive statement that 'formation' issues are governed by the CISG. The predominant opinion correctly assumes that the term 'formation' refers to the so-called 'external consensus', i.e., the mechanics of how the contract is concluded (which is dealt with in Arts. 14-24 CISG).[6] Other matters concerning the validity of the contract are explicitly stipulated to be outside the scope of the Convention under Art. 4(a) CISG and are therefore not governed by the CISG. These are, for example, matters referring to the so-called 'internal consensus' (i.e. incapacity, fraud and -- within certain limits [7] -- also mistake and misrepresentation) or validity issues arising from legislation, such as legal prohibitions, ordre public, export bans.[8]

2.3 Consequences for standard terms in a CISG contract

How do the general principles outlined above affect the use of standard terms under the CISG? The Convention does not provide specific rules for the use of standard terms. According to prevailing opinion, the question of whether standard terms have been effectively incorporated into a contract is governed by the Convention (the specific rules being derived from Art. 8 CISG on the interpretation of contracts, and probably also from the formation rules in Arts. 14 et seq. CISG), whereas the material validity of the standard terms (e.g., a control of their content according to standards of fairness) is governed by the applicable domestic law.[9] This distinction corresponds more or less to the distinction made above between 'external' and 'internal' consensus. [page 125]

3. THE INCORPORATION OF STANDARD TERMS

The German Supreme Court (Bundesgerichtshof) summarised in a famous decision the position regarding the incorporation of standard terms in a contract governed by the CISG as follows:[10]

It is submitted that, as a general proposition, this seems to be in line with the prevailing opinion in case law and legal writing.[11] In so far as the concrete details are concerned, however, the situation is less clear. [page 126]

3.2 Making the terms "available" or "mere reference"?

What exactly does an effective incorporation of standard terms into a CISG contract require?

In the above-mentioned decision, the Bundesgerichtshof took a rather restrictive approach towards the incorporation of standard terms by stating:[12]

According to the Bundesgerichtshof there are essentially two requirements for the incorporation of standard terms under the CISG: First, the 'offeror's'[13] intention to incorporate its standard terms must be apparent to the recipient; this will generally require a clear and understandable reference to those standard terms. Second, the offeror must transmit the text of the standard terms to the recipient or make it available otherwise.

It is the second requirement ('making available') that has instigated some debate, for it may be stricter than solutions found in domestic laws.[14] This requirement places on the offeror the burden to make the standard terms available to the recipient rather than require the recipient to enquire about the contents of the standard terms. The Bundesgerichtshof justified this on the basis that it is easier for the offeror to provide a copy of its standard terms than for the recipient to make enquiries as to their content and that while in domestic transactions the parties will often be familiar with 'typical' sets of standard terms, this will not usually be the case in the international context.

This Bundesgerichtshof's [15] 'making available' requirement has been criticised as being too strict; rather for a mere reference to the standard terms should suffice.[16] [page 127] Some courts seem to have adopted this more lenient approach.[17] At any rate, even if one follows the stricter approach of the Bundesgerichtshof, the 'making available' requirement should be interpreted generously. For example, if (the user can prove that) the other party knew the content of the user's standard terms, retransmission of those standard terms should not be required.[18] Similarly, it should normally be sufficient for the standard terms to be provided to the other party at the beginning of a longer-lasting business relationship, so that it is not necessary to resend the terms every time a contract is concluded during that relationship (provided of course that reference is made to them). What is more, actual usages take precedence under Art. 9 CISG.

3.3 The language issue

Language is another issue that arises with regard to the incorporation of standard terms into a CISG contract. In order for the standard terms to be effectively incorporated, in what language must the referring clause and/or the standard terms be drafted? Based on the standards set out in Art. 8 CISG it is submitted that one should ascertain whether the recipient understood or was at least in the given circumstances required to understand the language used.[19] This will usually be the case if the reference and the terms are drafted in the language in which the negotiations were conducted. In addition, the use of the recipient's language will in most cases be acceptable.[20]> However, it is doubtful whether the recipient should be required to understand certain 'world languages', such as English.[21] [page 128]

3.4 The battle of the forms

Specific problems concerning the use of standard terms arise in cases of the 'battle of forms',[22] i.e., where both parties to the contract try to impose their own set of standard terms. A typical scenario would be where the buyer sends his printed purchase order form in response to a seller's catalogue and the seller responds by sending his printed acceptance, with both forms referring to their own standard terms which are printed on the back of their forms.[23] If a dispute arises under such a contract, two issues will have to be addressed: the first issue will be whether a contract has in fact been concluded, and the second issue will be whether this contract was concluded on the seller's or buyer's terms.[24]

As the CISG does not contain any special rules concerning the battle of forms,[25] recourse should be had to the general principles underlying the Convention (Art. 7(2) CISG). A variety of solutions have been suggested in case law or legal writing. Accordingly, the two most important approaches are the so-called 'last shot rule' and the so-called 'knock out rule'.[26]

According to the 'last shot rule',[27] the contract is concluded on the terms of the final form used, without being objected by the other party. This view involves a straightforward application of Art. 19(1) CISG, in that it treats each subsequent form as a counter-offer, thereby rejecting the previous offer. Consequently, the terms of the contract result from the last form which was not objected by the offer's recipient and [page 129] has thus been accepted by both parties; typically, the recipient of an offer accepts the offer by performance.

It is submitted that this approach, while perhaps according most clearly with the language of the Convention, it is not satisfactory. If both parties were aware of how the 'last shot' principle worked, it might result in a 'ping-pong' series of communications intended to object to each other's standard terms (the so-called 'ping-pong' effect).[28] It would be a difficult task to decide when the final curtain for such objections falls.

According to the 'knock out rule', the contract is concluded on the basis of both parties' standard terms, in so far as they do not conflict with each other, whereas the conflicting parts of the respective forms are disregarded (i.e., 'knocked out'); the gaps in the contract resulting from the conflicting 'knocked out' standard terms are filled by applying the governing law of the contract, i.e., the CISG.[29] The rationale of this approach is that where the parties actually show (via performance) [30] that they wish to enter into a contract despite their conflicting standard terms, the parties are deemed to have agreed to waive the application of their standard terms, in so far as they are in conflict with each other.[31] The question remains whether this approach can be accommodated with the rule in Art. 19(1) CISG. It is submitted that this will be difficult, but that there is another way to apply the 'knock out' rule under the CISG. In fact, by virtue of their party autonomy (enshrined in Art. 6 CISG), the parties may be deemed to have departed from the Convention's rules on formation and in particular from Art. 19 CISG.[32] On that basis, it is submitted that the 'knock out rule' is the better solution for the battle of forms under the CISG.

Apart from being the law in a number of national jurisdictions, for example, in Germany, Austria and the United States (with the US Uniform Commercial Code),[33] [page 130] the 'knock out rule' is also the guiding (albeit not unqualified) principle of recent instruments for, inter alia, the harmonisation of international commercial laws, such as the UNIDROIT Principles of International Commercial Contracts (Art. 2.1.22 PICC),[34] the Principles of European Contract Law (Art. 2:209 PECL) and the Draft Common Frame of Reference (Art. II.4: 209 DCFR). Therefore, application of the 'knock out rule' under the CISG would bring the Convention in line with recent legal developments.

4. THE MATERIAL VALIDITY OF STANDARD TERMS

Once the standard terms are effectively incorporated into the contract, the question may arise whether their content should be subjected to some form of control according to standards of fairness. It is submitted that this is an issue of material validity which is not governed by the Convention but by the applicable domestic law, as provided for in Art. 4(a) CISG.[35]

Several domestic laws provide for such a control mechanism, even with respect to commercial contracts. One of the most prominent (and strictest) examples is German law. Accordingly, § 307 of the German Civil Code (Bürgerliches Gesetzbuch) states (in excerpts):[36]

Hence, standard terms used in a sales contract which leaving aside the CISG, are governed by national German law and subject to the reasonableness test under § 307 [page 131] of the German Civil Code. More specifically, the court would analyse whether the standard terms are incompatible with the essential principles of statutory provisions from which they deviate (§ 307(2) (no. 1)). In theory, it seems to be widely accepted that in case of a sales contract, governed by the CISG, the standard terms are to be measured against the provisions of the CISG as opposed to the German Civil Code.[37] In practice however, courts at times simply tend to apply the reasonableness standards developed with regard to the national Civil Code, without undertaking a fresh analysis of the respective standard terms under the CISG.[38] It is submitted that this is not appropriate and greater care should be taken in respecting the CISG's specific policy considerations.

5. INSTEAD OF A CONCLUSION: WHAT LIES AHEAD?

On the one hand, the lenient approach has its merits in light of the fact that CISG contracts are concluded between business entities which do not need as much protection as, for example, consumers.[39] Moreover, a number of practical problems may arise under the 'making available' requirement, particularly in E-Commerce transactions which are concluded by exchange of e-mails: What does 'making available' precisely mean in that context? Is it sufficient for the user of standard terms to refer the other party to its website where the standard terms can be downloaded? Is it sufficient to send the website link by e-mail? Or must a copy of the standard terms be attached to the e-mail, by which the user of standard terms makes its offer? If the latter, must such an attachment be sent as a pdf file, and if so, should the user provide a website link for free access to download the Adobe Reader programme?[40] [page 132]

Conversely, if one thinks about a plain and simple contract concluded by letter or fax, there is considerable force in the argument that it is easier and from an overall economic perspective cheaper for the user to attach its standard terms to its offer, rather than having the other party ask for it first which may cause delay. It should be possible to develop suitable standards for the 'making available' requirement for the particularities of electronic commerce. In the author's opinion, it is doubtful whether it is sufficient for the user of standard terms to simply send the other party a link to a website where its standard terms can be downloaded.[41] To attach the standard terms to an e-mail in a format which the other party can easily access is preferable.[42] Irrespective of which solution will finally be agreed, the first and foremost task is to develop one clear, precise and uniform solution, on which parties can rely. In addition, suffice it to briefly mention here that the same is true with regard to a rule on surprising standard terms.[43] Here, too, a uniform solution should be developed; inspiration may be drawn, for example, from Art. 2.1.20 PICC.

Secondly, it is highly desirable to put an end to the dispute between the 'last shot rule' and the 'knock out rule'. As has been explained above, the preferable solution is the 'knock out rule'. Inspiration can be drawn from the corresponding provisions in the PICC, or -- even better -- the PECL or the DCFR, the wording of which is more precise than that of the PICC. However, both solutions have their merits and neither would be wholly inappropriate for international commerce so the crucial task again would be to agree on one of them so as to provide legal certainty.

Thirdly, the law of international commerce and in particular the CISG would profit considerably from a rule which sets a uniform standard concerning the material control of standard terms (e.g. under a reasonableness or fairness test) and which thus takes this specific area of the law away from the national legislators. Ideally, it is submitted, such a rule would be very restrictive in its depth of control as party autonomy is the cornerstone of both international commerce and the CISG as per Art. 6 CISG.

Finally, to become reality, in theory the first two submissions could largely be settled if courts and legal scholars agreed on and promoted a common solution. Nonetheless, [page 133] this may be illusionary and insufficient for solving the third issue. Eventually, the only solution lies in some form of legislative guidance. As a revision of the CISG itself seems to be rather unlikely at present, one might think about creating a new instrument on the use of standard terms in international commerce, a project which admittedly would be a long shot but one which may be worthwhile.[page 134]

FOOTNOTES

* Professor Dr. Peter Huber LL.M. (London) holds the chair for private law, private international law and comparative law at Johannes Gutenberg University, Mainz, Germany.

1. See, for example, Schlechtriem, P., in Schlechtriem, P. and Schwenzer, I., Commentary on the UN Convention on the International Sale of Goods (CISG), 2005, Oxford University Press, Art. 14, at para. 16; Schlechtriem, P., "Kollidierende Geschäftsbedingungen im internationalen Vertragsrecht" in Thume, K. H. (ed), Transport- und Vertriebsrecht 2000, Festschrift für Professor Dr. Rolf Herber, 1999, Luchterhand, at pp. 36 ff, translated into English: "Battle of the Forms in International Contract Law: Evaluation of approaches in German law, UNIDROIT Principles, European Principles, CISG; UCC approaches under consideration", available at: <http://www.cisg.law.pace.edu/cisg/biblio/schlechtriem5.html>.

2. Huber, P., in Huber, P. and Mullis, A., The CISG, 2007, Sellier European Law Publishers, at p. 20.

3. See, for example, Art. 5 CISG on the issue of limitation of claims which is not governed by the CISG; Huber, P., in Huber and Mullis, supra fn 2, at p. 29.

4. See Ferrari, F., "The Interaction Between the United Nations Conventions on Contracts for the International Sale of Goods and Domestic Remedies" (2007) 71 Rabels Zeitschrift für ausländisches und Internationales Privatrecht (RabelsZ) 52; Leyens, P., Review of the Convention on Contracts for the International Sale of Goods (CISG) 2003-2004, 2004, Sellier European Law Publishers, at p. 3; Hartnell, H. E., "Rousing the Sleeping Dog: The Validity Exception to the Convention on Contracts for the International Sale of Goods" (1993) 18 Yale Journal of International Law 1; Huber, P., "UN-Kaufrecht und Irrtumsanfechtung" (1994) Zeitschrift für Europäisches Privatrecht (ZEuP) 585; Huber, P., in Huber and Mullis, supra fn 2, at pp. 21 ff.

5. Schlechtriem, P., in Schlechtriem and Schwenzer, supra fn 1, Art. 4, at para. 7; Ferrari, F., in Schlechtriem and Schwenzer, Kommentar zum Einheitlichen UN-Kaufrecht, 2004, 4th ed., Verlag C. H. Beck, Art. 4, at para. 6; Huber, P., in Huber and Mullis, supra fn 2, at p. 21. But see also the differing opinions of Lessiak, R., "UNCITRAL-Kaufrechtsabkommen und Irrtumsanfechtung" (1989) Juristische Blätter (JBl) 487; Hartnell, H. E. (1993) 18 Yale Journal of International Law 1; Geneva Pharmaceuticals Technology Group v Barr Laboratories (2002) SD NY, CISG-Online No. 653.

6. (Austrian) Oberster Gerichtshof 22 October 2001, CISG-Online No. 613; (Austrian) Oberster Gerichtshof 6 February 1996, CISG-Online No. 224; Ferrari, F., in Schlechtriem and Schwenzer, supra fn 5, Art. 4, at para. 15; Huber, P., in Huber and Mullis, supra fn 2, at pp. 21 ff.

7. For further detail see Huber, P., in Huber and Mullis, supra fn 2, at pp. 22 ff.

8. Huber, P., in Huber and Mullis, supra fn 2, at p. 22; Ferrari, F., in Schlechtriem and Schwenzer, supra fn 5, Art. 4, at para. 18ff.

9. Schlechtriem, P., in Schlechtriem and Schwenzer, supra fn 1, Art. 14, at para. 16; Gruber, U., in Münchener Kommentar zum Bürgerlichen Gesetzbuch, 2008, 5th ed. Verlag C. H. Beck, Art. 14, at para. 27; Ferrari, F., in Schlechtriem and Schwenzer, supra fn 5, Art. 4, at para. 20; Westermann, H. P., in Münchener Kommentar zum Bürgerlichen Gesetzbuch, in this fn, Art. 4, at para. 6.

10. (German) Bundesgerichtshof 31 October 2001, (2002) Internationales Handelsrecht (IHR) 14 = CISG-Online No. 617, English translation available at: <http://cisgw3.law.pace.edu/cases/011031g1.html>.

11. Schlechtriem, P., in Schlechtriem and Schwenzer, supra fn 1, Art. 14, at para. 16; Gruber, U., supra fn 9, "Vor Art. 14", at para. 4; Ferrari, F., in Münchener Kommentar zum Handelsgesetzbuch, supra fn 9, Art. 14, at para. 5; Mankowski, P., in Ferrari, F., Kieninger, E.-M., Mankowski, P., Otte, K., Saenger, I. and Staudinger, A., Internationales Vertragsrecht Kommentar, 2007, Verlag C. H. Beck, "Vor Art. 14", at para. 21; (Austrian) Oberster Gerichtshof 6 February 1996, CISG-Online No. 224; (German) Oberlandesgericht Dusseldorf 21 April 2004, (2005) Internationales Handelsrecht (IHR) 24 = CISG-Online No. 915; (Austrian) Oberlandesgericht Linz 8 August 2005, (2005) Internationales Handelsrecht (IHR), 249 = CISG-Online No. 1087.

12. See supra fn 10.

13. The term 'offeror' being understood as the party that wants to introduce its standard terms.

14. Thus, for example, domestic German law would -- in this respect (not in others) -- take a less strict approach in many cases.

15. Which has been followed, for example, by the (German) Oberlandesgericht Düsseldorf 21 April 2004, (2005) Internationales Handelsrecht (IHR) 24 = CISG-Online No. 915, stating further that where a copy of the standard terms sent by the offeror was partly illegible, this need not necessarily mean that the offeror failed to make available the standard terms, because in these circumstances the recipient should ask for clarifications. For support of the position of the Bundesgerichtshof see Magnus, U., "Incorporation of Standard Contract Terms under the CISG" in Andersen, C. and Schroeter, U. (eds.), Sharing International Commercial Law across National Boundaries: Festschrift for Albert H. Kritzer on the Occasion of his Eightieth Birthday, 2008, Wildy, Simmonds & Hill Publishers, at p. 303; Mankowski, P., supra fn 11, "Vor Art. 14", at paras. 28 ff.; Gruber, U., supra fn 9, Art. 14, at para. 29.

16. Schmidt-Kessel, M., in Schlechtriem and Schwenzer, supra fn 1, Art. 8, at para. 53; Schmidt-Kessel, M. and Meyer, L., "Allgemeine Geschäftsbedingungen und UN-Kaufrecht" (2008) Internationales Handelsrecht (IHR) 178. See also the doubts raised by Schlechtriem, P., in Schlechtriem and Schwenzer, supra fn 1, Art. 14, at para. 16, fn. 83b. See further (for a case-by-case analysis) Berger, K. P., "Die Einbeziehung von AGB in internationale Kaufverträge", in Zivil- und Wirtschaftsrecht im Europäischen und Clobalen Kontext, Festschrift für Norbert Horn, 2006, Walter de Gruyter Verlag, at pp. 16 ff.

17. See, for instance, (Austrian) Oberster Gerichtshof 17 December 2003, (2004) Internationales Handelsrecht (IHR) 153 = CISG-Online No. 828, where the court seems to accept that standard terms may be validly incorporated even if they are not made part of the offer, provided that there is a clause referring to these terms which is so clear that a reasonable party in the shoes of the recipient would have understood it; the issue was not explicitly addressed, however, and the main issue in that regard was the language issue. For further references see Schmidt-Kessel, M., in Schlechtriem and Schwenzer, supra fn 1, Art. 8, at para. 53; Schlechtriem, P., in Schlechtriem and Schwenzer, supra fn 1, Art. 14, at para. 16.

18. See Magnus, U., "Standard Contract Terms under the CISG", supra fn 15, at p. 322.

19. Huber, P., in Huber and Mullis, supra fn 2, at p. 32; see also Schmidt-Kessel, M., in Schlechtriem and Schwenzer, supra fn 1, Art. 8, at para. 54; (Austrian) Oberster Gerichtshof 17 December 2003, (2004) Internationales Handelsrecht (IHR) 148, at pp. 153ff. = CISG-Online No. 828.

20. See (German) Oberlandesgericht Dusseldorf 21 April 2004, (2005) Internationales Handelsrecht (IHR) 24 = CISG-Online No. 915.

21. For a more demanding position in that respect see (Austrian) Oberster Gerichtshof 17 December 2003, (2004) Internationales Handelsrecht (IHR) 148, at p. 154 = CISG-Online No. 828 (according to which German, French and English could possibly be regarded as world languages).

22. For literature on this issue see Schlechtriem, P., "Battle of the Forms in International Contract Law", available at: <http://www.cisg.law.pace.edu/cisg/biblio/schlechtriem5.html>; Viscasillas, M., "Battle of the Forms Under the 1980 United Nations Convention on Contracts for the International Sale of Goods: A Comparison with Section 2-207 UCC and the UNIDROIT Principles" (1998) 10 Pace International Law Review 97; Viscasillas, M., "Battle of Forms and the Burden of Proof: An analysis of BGH 9 January 2002" (2002) 6 Vindobona Journal of International Commercial Law and Arbitration 217.

23. The battle of the forms only arises if both parties have fulfilled the requirements for an effective incorporation, the standard of which may differ according to which court decides the issue; see supra sub-heading 3.2.

24. Mullis, A., in Huber and Mullis, supra fn 2, at p. 92.

25. The issue was discussed in Vienna but proposals to deal with it were rejected. See Official Records, at pp. 288ff, available at: <http://www.uncitral.org/pdf/english/texts/sales/cisg/a-conf-97-19-ocred-e.pdf>. See further Schlechtriem, P., in Schlechtriem and Schwenzer, supra fn 1, Art. 19, at paras. 4 and 19.

26. Other approaches are, for example, the 'first shot rule' (which is applied by Dutch law, see Art. 6:225(3) Dutch Civil Code) or the suggestion to deal with the battle of the forms under the applicable national law (see Vergne, F., "The 'Battle of the Forms' Under the 1980 United Nations Convention on Contracts for the International Sale of Goods" (1985) 33 American Journal of Comparative Law 233). Nonetheless, the first shot rule is incompatible with the rules in Art. 19 CISG, and recourse to national law is barred by Art. 7(2) CISG, as one can find general principles underlying the CISG.

27. See Farnsworth, E. A., in Bianca, C. M. and Bonell, M. J., Commentary on the International Sales Law, 1987, Guiffrè, Art. 19, at para. 2.5.; Enderlein, F. and Maskow, D., International Sales Law Commentary, 1992, Oceana Publications, Art. 19, at para. 10; Ferrari, F., supra fns 9 and 11, Art. 19 CISG, at para. 15; Viscasillas, M., "Battle of the Forms Under the CISG", supra fn 22, at pp. 117 ff and 144 ff; see further in that direction - although not explicitly deciding the issue Magellan International Corporation v. Salzgitter Handel GmbH (1999) ND. Ill., CISG-Online No. 439.

28. See, for example, Viscasillas, M., "Battle of the Forms Under the CISG", supra fn 22, p. 97 at para. IV. D.

29. See Schlechtriem, P., in Schlechtriem and Schwenzer, supra fn 1, Art. 19, at para. 20; Mullis, A., in Huber and Mullis, supra fn 2, at p. 94; Honnold, J. O., Uniform Law for International Sales under the 1980 United Nations Convention, 1999, Kluwer Law International, at para. 170.4; Gruber, U., in Münchener Kommentar zum BOB, Art. 19, at para. 20. The (German) Bundesgerichtshof 9 January 2002, (2002) Internationales Handelsrecht (IHR) 16 = CISG-Online No. 651 confirmed the 'knock out' rule to be the prevailing opinion; the court, however, did not have to choose between the two solutions as it found that both would lead to the same result in the case at hand. The matter was also left open, for example, in (German) Oberlandesgericht Düsseldorf 25 July 2003, CISG-Online No. 919; (Austrian) Oberster Gerichtshof 13 September 2001, (2002) Internationales Handelsrecht (IHR) 74, at p. 76 = CISG-Online No. 644.

30. For more details on this point see Magnus, U., "Last Shot vs. Knock Out - Still Battle over the Battle of Forms under the CISG", in Commercial Law Challenges in the 21st Century, Jan Hellner in memoriam, 2007, Iustus Förlag, at pp. 185 and. 195ff.

31. Mullis, A., in Huber and Mullis, supra fn 2, at p. 94.

32. Ibid.; Gruber, U., supra fn 9, Art. 19, at para. 24.

33. White, J. J. in White, J. J. and Summers, R S., Uniform Commercial Code, 2000, West Group, at p. 34 (but see also the differing opinion of Prof. Summers at pp. 34 ff, who argues that the offeror's terms prevail). In 2003, Article 2 of the UCC was revised, and amendments in § 2-207 UCC now clarify that no preference is given to the terms of either party (see further at: <http://www.nccusl.org/Update/uniformact_summaries/uniformacts-s-ucc22003.asp>). So far the revised version of Article 2 UCC has not yet been adopted by any state.

34. See the comments by Naude, T., in Vogenauer, S. and Kleinheisterkamp, J., Commentary on the Unidroit Principles of International Commercial Contracts, 2009, Oxford University Press, at Art. 2.1.22.

35. Magnus, U., in Staudingers Kommentar zum Bürgerlichen Gesetzbuch, Wiener UN-Kaufrecht (CISC), 2005, Sellier de Gruyter, Art. 4, at para. 24.

36. The English translation of the German Civil Code is available at: < http://www.gesetze-im-internet.de/englisch_bgb/englisch_bgb.html>.

37. Huber, P., in Munchener Kommentar zum BGB, supra fn 9, Art. 45, at para. 30; Ferrari, F., supra fns 9 and 11, "Vor Art. 14", at para. 5.

38. See for example (German) Oberlandesgericht Braunschweig 28 October 1999, CISG-Online No. 510; (German) Oberlandesgericht Zweibrücken 31 March 1998, CISG-Online No. 481 (judgment later set aside by Bundesgerichtshof on other grounds), (German) Bundesgerichtshof 24 March 1999, CISG-Online No. 396.

39. Huber, P., in Huber and Mullis, The CISG, at p. 32.

40. See in detail Mankowski, P., in Ferrari, Kieninger, Mankowski, Otte, Saenger and Staudinger, supra fn 11, "Vor Art. 14", at paras. 32 ff.

41. This was for example suggested by Schwenzer, I. and Mohs, F., "Old Habits Die Hard: Traditional Contract Formation in a Modern World" (2006) Internationales Handelsrecht (IHR) 239, at p. 241. A similar approach seems to be underlying the 2005 UN Convention on the Use of Electronic Communications in International Contracts which in Art. 10(2) states (as a general rule) that the time of receipt of an electronic communication is the time when it becomes capable of being retrieved by the addressee at an electronic address designated by the addressee.

42. Art. II.-9:103(2) DCFR requires standard terms to be made available to the other party in 'textual form' which is defined in Art. I.-1:105(2) DCFR as 'a text which is expressed in alphabetical or other intelligible characters by means of any support which permits reading, recording of the information contained in the text and its reproduction in tangible form'. Quaere, what precisely this means for the issue raised here.

43. See Schmidt-Kessel, M., in Schlechtriem and Schwenzer, supra fn 1, Art. 8, at para. 57, for further references.