MLA

Morse, William R. (William Reginald), 1874-1939. William Morse to Mother from Shanghai, boat on Yangtze River, Yichang (Ichang). 1, folder 2. 1909 November. https://collections.library.yale.edu/catalog/33391158.

APA, 6th edition

Morse, William R. (William Reginald), 1874-1939. (["1, folder 2"])(1909 November)[William Morse to Mother from Shanghai, boat on Yangtze River, Yichang (Ichang)]. https://collections.library.yale.edu/catalog/33391158.