MLA

Dellenbaugh, Frederick Samuel, 1853-1935. New York. Box 2, folder 41. 1921. https://collections.library.yale.edu/catalog/2017814.

APA, 6th edition

Dellenbaugh, Frederick Samuel, 1853-1935. (["Box 2, folder 41"])(1921)[New York]. https://collections.library.yale.edu/catalog/2017814.