MLA

Viewing Astronomical Instrument on Yenching University Group Outing to City Wall, Beijing, China, Ca. 1920-1930. 1920. https://collections.library.yale.edu/catalog/11427166.

APA, 6th edition

Viewing astronomical instrument on Yenching University group outing to city wall, Beijing, China, ca. 1920-1930. (1920). [Group portraits (AAT), photographs (AAT)]. https://collections.library.yale.edu/catalog/11427166.