MLA

McClintock, Walter, 1870-1949. FS-86. Night Dancers.. Box 147, folder 7828. undated. https://collections.library.yale.edu/catalog/10453406.

APA, 6th edition

McClintock, Walter, 1870-1949. (["Box 147, folder 7828"])(undated)[FS-86. Night Dancers.]. https://collections.library.yale.edu/catalog/10453406.