MLA

Erdoes, Richard, 1912-2008. Buffy, Angela Harjos Little Horn. Box 56 | Hokahay, Indian Civil Rights. 1973, undated. https://collections.library.yale.edu/catalog/2084394.

APA, 6th edition

Erdoes, Richard, 1912-2008. (["Box 56 | Hokahay, Indian Civil Rights"])(1973, undated)[Buffy, Angela Harjos Little Horn]. https://collections.library.yale.edu/catalog/2084394.