MLA

Horstmann, Dorothy M. (Dorothy Millicent), 1911-. Russia. Box 43, folder 17 - 18. 1959. https://collections.library.yale.edu/catalog/10015654.

APA, 6th edition

Horstmann, Dorothy M. (Dorothy Millicent), 1911-. (["Box 43, folder 17 - 18"])(1959)[Russia]. https://collections.library.yale.edu/catalog/10015654.