MLA

Pratt, Richard Henry, 1840-1924. Indian prisoners (stereograms), 2 items. Box 23a, folder 747. n.d.. https://collections.library.yale.edu/catalog/2041169.

APA, 6th edition

Pratt, Richard Henry, 1840-1924. (["Box 23a, folder 747"])(n.d.)[Indian prisoners (stereograms), 2 items]. https://collections.library.yale.edu/catalog/2041169.