MLA

Bainton, Roland H. (Roland Herbert), 1894-1984. Ahlstrom, Sydney. 55, folder 802. undated. https://collections.library.yale.edu/catalog/33591437.

APA, 6th edition

Bainton, Roland H. (Roland Herbert), 1894-1984. (["55, folder 802"])(undated)[Ahlstrom, Sydney]. https://collections.library.yale.edu/catalog/33591437.