MLA

Stein, Gertrude, 1874-1946. Maratier, George. Box 116, folder 2431-2433. 1928-44, n.d.. https://collections.library.yale.edu/catalog/17105753.

APA, 6th edition

Stein, Gertrude, 1874-1946. (["Box 116, folder 2431-2433"])(1928-44, n.d.)[Maratier, George]. https://collections.library.yale.edu/catalog/17105753.