Cite

Envelopes, 3 types (unused)

MLA

Dreier, Katherine S. (Katherine Sophie), 1877-1952. Envelopes, 3 types (unused). Box 90, folder 2334. n.d.. https://collections.library.yale.edu/catalog/2014463.

APA, 6th edition

Dreier, Katherine S. (Katherine Sophie), 1877-1952. (["Box 90, folder 2334"])(n.d.)[Envelopes, 3 types (unused)]. https://collections.library.yale.edu/catalog/2014463.