"The corresponding rule in Article 91 ULIS is essentially in the same terms as [CISG] Article 85. . . . Article 91 ULIS did not lay down, [however] as [CISG Article 85 expressly does, that the seller must be either in possession of the goods or able to control their disposition." Eberstein in Commentary on the UN Convention on the International Sale of Goods, Peter Schlechtriem ed. (Oxford 1998) 667.
CISG Article 85 ULIS Article 91 If the buyer is in delay in Where the buyer is in delay taking delivery of the goods in taking delivery of the goods or, where payment of the or in paying the price, the seller price and delivery of the shall take reasonable steps to goods are to be made preserve the goods; he shall concurrently, if he fails to have the right to retain them pay the price, and the seller until he has been reimbursed his is either in possession of the reasonable expenses by the buyer. goods or otherwise able to control their disposition, the seller must take such steps as are reasonable in the circumstances to preserve them. He is entitled to retain them until he has been reimbursed his reasonable expenses by the buyer.