MLA

Simpson, Randolph Linsly, 1927-1992. James Van Der Zee, NY Children-Dance Class: five young girls strike poses. Postcard. Box 25, folder 1036. 1928. https://collections.library.yale.edu/catalog/32312569.

APA, 6th edition

Simpson, Randolph Linsly, 1927-1992. (["Box 25, folder 1036"])(1928)[James Van Der Zee, NY Children-Dance Class: five young girls strike poses. Postcard]. https://collections.library.yale.edu/catalog/32312569.