Art. 82 CISG
(1) The buyer loses the right to declare the contract avoided or to require the seller to deliver substitute goods if it is impossible for him to make restitution of the goods substantially in the condition in which he received them.
(2) The preceding paragraph does not apply:
(a) if the impossibility of making restitution of the goods or of making restitution of the goods substantially in the condition in which the buyer received them is not due to his act or omission;
(b) if the goods or part of the goods have perished or deteriorated as a result of the examination provided for in article 38; or
(c) if the goods or part of the goods have been sold in the normal course of business or have been consumed or transformed by the buyer in the course of normal use before he discovered or ought to have discovered the lack of conformity.
The Secretariat Commentary on Art. 67 of the 1978 New York Draft, predecessor to Art. 82 CISG, gives insight into the drafters' unterstanding on the eve of the 1980 Vienna Diplomatic Conference.
Commentary on the Draft Convention on Contracts for the International Sale of Goods, prepared by the Secretariat (UN Doc. A/CONF.97/5), in: United Nations Conference on Contracts for the International Sale of Goods, Vienna, 10 March – 11 April 1980, Official Records: Documents of the Conference and Summary Records of the Plenary Meetings and of the Meetings of the Main Committees, New York: United Nations (1991), pp. 14 et seq., at pp. 57—58
Overview of case law on Art. 82 CISG: UNCITRAL Digest
The UNCITRAL Digest on the CISG can be used as a starting point to discover the relevant case law on this article.