MLA

Barbour, Margaret Hart. Sunday School Children, Shanghai, China, Ca. 1923. 1923. https://collections.library.yale.edu/catalog/11420955.

APA, 6th edition

Barbour, M. H. (1923). Sunday School children, Shanghai, China, ca. 1923 [Group portraits (AAT), photographs (AAT)]. https://collections.library.yale.edu/catalog/11420955.