MLA

Wilson, Edmund, 1895-1972. Skeleton. Box 204, folder 5006. n.d.. https://collections.library.yale.edu/catalog/2005088.

APA, 6th edition

Wilson, Edmund, 1895-1972. (["Box 204, folder 5006"])(n.d.)[Skeleton]. https://collections.library.yale.edu/catalog/2005088.