[For more current case annotated texts by this author, see Bernstein & Lookofsky, Understanding the CISG in Europe, 2d ed. (2003) and Lookofsky, Understanding the CISG in the USA, 2d ed. (2004).]
332. Article 11 dispenses with the formal requirement, posed by some domestic laws, that sales contracts be concluded in or evidenced by writing; similarly, CISG Part II contains no writing requirements with respect to the constituent parts of the contract (the offer and the acceptance), and Article 29 dispenses with writing requirements as regards contract modification.
Because some States still attach importance to requirements such as these, Article 12 of the CISG provides that the various Convention rules which permit non-written contracts, modifications, etc., do not apply where any party has his place of business in a Contracting State which has made a declaration under Article 96. Argentina, Belarus, Chile, China, Estonia, Hungary, Lithuania, Ukraine and the Russian Federation have all made such a declaration.
The effect of an Article 96 declaration is that the declaring State is not bound by Article 11, etc. Therefore, that State's formal requirements remain applicable to international sales subject to the CISG. However, where only one of the parties to an international sales contract resides in a such a declaring State, the forum court must resolve a conflict of laws. The forum court asked to apply the formal requirements of the declaring State (as opposed to Article 11, etc.) should do so only when its rules private international law lead to the application of the declaring State's law.