Burden of proof under Art. 77 CISG
Although the CISG does not explicitly provide for the allocation of the burden of proof (except in Art. 79(1) CISG), a US court has found the burden of proof regarding Art. 77 CISG to be governed by the CISG:
U.S. District Court for the Central District of California
USA, 25 April 2011 – SACV 09-00530-CJC(ANx), CISG-online 4657
As with other affirmative defenses to breach of contract claims under the CISG, the breaching party relying on Art. 77 CISG bears the burden of proof of showing that the non-breaching party failed to take reasonable measures to mitigate the loss and the amount by which the non-breaching party’s damages should be reduced as a result.