MLA

Stein, Gertrude, 1874-1946. Holograph drafts. Box 27, folder 537-538. n.d.. https://collections.library.yale.edu/catalog/2067418.

APA, 6th edition

Stein, Gertrude, 1874-1946. (["Box 27, folder 537-538"])(n.d.)[Holograph drafts]. https://collections.library.yale.edu/catalog/2067418.