MLA

Canby, Henry Seidel, 1878-1961. "U" general. Box 6, folder 206. 1917-45. https://collections.library.yale.edu/catalog/17170200.

APA, 6th edition

Canby, Henry Seidel, 1878-1961. (["Box 6, folder 206"])(1917-45)["U" general]. https://collections.library.yale.edu/catalog/17170200.