MLA

Luhan, Mabel Dodge, 1879-1962. "Lawrence Vol. III". Box 89, folder 2258. 1937-39, n.d.. https://collections.library.yale.edu/catalog/2040619.

APA, 6th edition

Luhan, Mabel Dodge, 1879-1962. (["Box 89, folder 2258"])(1937-39, n.d.)["Lawrence Vol. III"]. https://collections.library.yale.edu/catalog/2040619.