MLA

Pratt, Richard Henry, 1840-1924. Indian chiefs, 3 items. Box 23, folder 734. n.d.. https://collections.library.yale.edu/catalog/2029919.

APA, 6th edition

Pratt, Richard Henry, 1840-1924. (["Box 23, folder 734"])(n.d.)[Indian chiefs, 3 items]. https://collections.library.yale.edu/catalog/2029919.