MLA

Anderson, Margaret C., 1886-1973. Gurdjieff, Georges Ivanovitch. Box 20, folder 361. circa 1930-1956. https://collections.library.yale.edu/catalog/2018434.

APA, 6th edition

Anderson, Margaret C., 1886-1973. (["Box 20, folder 361"])(circa 1930-1956)[Gurdjieff, Georges Ivanovitch]. https://collections.library.yale.edu/catalog/2018434.