MLA

H. D. (Hilda Doolittle), 1886-1961. Constantine, Murry. Box 9, folder 298. n.d.. https://collections.library.yale.edu/catalog/10061382.

APA, 6th edition

H. D. (Hilda Doolittle), 1886-1961. (["Box 9, folder 298"])(n.d.)[Constantine, Murry]. https://collections.library.yale.edu/catalog/10061382.