MLA

Cortissoz, Royal, 1869-1948. La Farge, John (Sketchbook). Box 7, folder 281. n.d.. https://collections.library.yale.edu/catalog/2053974.

APA, 6th edition

Cortissoz, Royal, 1869-1948. (["Box 7, folder 281"])(n.d.)[La Farge, John (Sketchbook)]. https://collections.library.yale.edu/catalog/2053974.