MLA

Luhan, Mabel Dodge, 1879-1962. Mabel Dodge Luhan watercolor. ART, folder 25. n.d.. https://collections.library.yale.edu/catalog/2003118.

APA, 6th edition

Luhan, Mabel Dodge, 1879-1962. (["ART, folder 25"])(n.d.)[Mabel Dodge Luhan watercolor]. https://collections.library.yale.edu/catalog/2003118.