These 2 volumes are a slightly revised version of the substantive reports prepared by the Max Planck Institute in Hamburg (Director: Professor Konrad Zweigert) for the Rome Institute for the Unification of Private Law. They were designed to serve as a basis for the elaboration and discussion of a new uniform law on this subject matter, which would supplement the 1964 Hague conventions on a Uniform Law on the International Sale of Goods and Uniform Law on the Formation of Contract for the International Sale of Goods.
Gray, Whitmore. Review of The Validity of Sales Contracts: A Comparative Study, Max Planck Institute. Mod. L. & Soc'y 2 (1968): 164-7.