MLA

Beinecke, Edwin J. (Edwin John), 1886-1970. Printed illustrations of Robert Louis Stevenson and others. Box 66, folder 1542-1545. undated. https://collections.library.yale.edu/catalog/2033699.

APA, 6th edition

Beinecke, Edwin J. (Edwin John), 1886-1970. (["Box 66, folder 1542-1545"])(undated)[Printed illustrations of Robert Louis Stevenson and others]. https://collections.library.yale.edu/catalog/2033699.