MLA

Oastler, Frank Richard, 1871-1936. Printed map previously in the envelope at the front of 1915 Wyoming Album I. Box 69, folder 71. undated. https://collections.library.yale.edu/catalog/15831931.

APA, 6th edition

Oastler, Frank Richard, 1871-1936. (["Box 69, folder 71"])(undated)[Printed map previously in the envelope at the front of 1915 Wyoming Album I]. https://collections.library.yale.edu/catalog/15831931.