MLA

Luhan, Mabel Dodge, 1879-1962. Feshin, Nikolai Ivanovich: paintings of Dorothy Brett, Willa Cather, Mary Hamlin, Spud Johnson, Elizabeth Shepley Sergeant and Ella Young. Box 80, folder 2223. n.d.. https://collections.library.yale.edu/catalog/2002411.

APA, 6th edition

Luhan, Mabel Dodge, 1879-1962. (["Box 80, folder 2223"])(n.d.)[Feshin, Nikolai Ivanovich: paintings of Dorothy Brett, Willa Cather, Mary Hamlin, Spud Johnson, Elizabeth Shepley Sergeant and Ella Young]. https://collections.library.yale.edu/catalog/2002411.