MLA

Richardson, Dorothy M. (Dorothy Miller), 1873-1957. WANTED: THE PLAY-SPIRIT: typescript (carbon) 4 p.. Box 8, folder 186. n.d.. https://collections.library.yale.edu/catalog/16495650.

APA, 6th edition

Richardson, Dorothy M. (Dorothy Miller), 1873-1957. (["Box 8, folder 186"])(n.d.)[WANTED: THE PLAY-SPIRIT: typescript (carbon) 4 p.]. https://collections.library.yale.edu/catalog/16495650.