MLA

Steinberg, Saul, 1914-1999. Kunming 1943-1944. Box 80, folder 1819. circa 1988. https://collections.library.yale.edu/catalog/16856386.

APA, 6th edition

Steinberg, Saul, 1914-1999. (["Box 80, folder 1819"])(circa 1988)[Kunming 1943-1944]. https://collections.library.yale.edu/catalog/16856386.