MLA

Erdoes, Richard, 1912-2008. Horses, Riders, Travois. Box 45 | Plains Indian History I. 1971-1980, undated. https://collections.library.yale.edu/catalog/10256087.

APA, 6th edition

Erdoes, Richard, 1912-2008. (["Box 45 | Plains Indian History I"])(1971-1980, undated)[Horses, Riders, Travois]. https://collections.library.yale.edu/catalog/10256087.