MLA

McClintock, Walter, 1870-1949. Y-1229, 961a. Buckskin Horse Showing Black Line. Back.. Box 75, folder 4358. 1905 1941. https://collections.library.yale.edu/catalog/2010816.

APA, 6th edition

McClintock, Walter, 1870-1949. (["Box 75, folder 4358"])(1905 1941)[Y-1229, 961a. Buckskin Horse Showing Black Line. Back.]. https://collections.library.yale.edu/catalog/2010816.