MLA

Lowenfels, Walter, 1897-1976. "Selby," typescript. Box 94, folder 1430. undated. https://collections.library.yale.edu/catalog/17174425.

APA, 6th edition

Lowenfels, Walter, 1897-1976. (["Box 94, folder 1430"])(undated)["Selby," typescript]. https://collections.library.yale.edu/catalog/17174425.