MLA

Luhan, Mabel Dodge, 1879-1962. ----, Elizabeth. Box 39, folder 1127-1132. 1915-27, n.d.. https://collections.library.yale.edu/catalog/17085369.

APA, 6th edition

Luhan, Mabel Dodge, 1879-1962. (["Box 39, folder 1127-1132"])(1915-27, n.d.)[----, Elizabeth]. https://collections.library.yale.edu/catalog/17085369.