Cite

40. [Horses Grazing on a Prairie.]

MLA

McClintock, Walter, 1870-1949. 40. [Horses Grazing on a Prairie.]. Box 60, folder 2978. 1941. https://collections.library.yale.edu/catalog/2008422.

APA, 6th edition

McClintock, Walter, 1870-1949. (["Box 60, folder 2978"])(1941)[40. [Horses Grazing on a Prairie.]]. https://collections.library.yale.edu/catalog/2008422.