MLA

Luhan, Mabel Dodge, 1879-1962. Unidentified. Box 74, folder 2066-2074. 1907-48, n.d.. https://collections.library.yale.edu/catalog/2014284.

APA, 6th edition

Luhan, Mabel Dodge, 1879-1962. (["Box 74, folder 2066-2074"])(1907-48, n.d.)[Unidentified]. https://collections.library.yale.edu/catalog/2014284.