MLA

Bainton, Roland H. (Roland Herbert), 1894-1984. Welch, Claude. 56, folder 908. undated. https://collections.library.yale.edu/catalog/33599334.

APA, 6th edition

Bainton, Roland H. (Roland Herbert), 1894-1984. (["56, folder 908"])(undated)[Welch, Claude]. https://collections.library.yale.edu/catalog/33599334.