MLA

Children Seated in a Classroom with a Missionary Sister Looking on, Canada, Ca. 1920-1940. 1920. https://collections.library.yale.edu/catalog/11477970.

APA, 6th edition

Children seated in a classroom with a missionary sister looking on, Canada, ca. 1920-1940. (1920). [General views (AAT), photographic postcards (AAT), photographs (AAT)]. https://collections.library.yale.edu/catalog/11477970.