Cite

Wagon Trains [1 of 40 slides]

MLA

Erdoes, Richard, 1912-2008. Wagon Trains [1 of 40 slides]. Box 76 | Western History, White. 1975-1976, undated. https://collections.library.yale.edu/catalog/2099339.

APA, 6th edition

Erdoes, Richard, 1912-2008. (["Box 76 | Western History, White"])(1975-1976, undated)[Wagon Trains [1 of 40 slides]]. https://collections.library.yale.edu/catalog/2099339.