MLA

La Revellière-Lépeaux, Louis-Marie de, 1753-1824. Seven sketches of Celtic monuments, accompanied by explanatory notes in pencil. Box 5, folder 156. n.d.. https://collections.library.yale.edu/catalog/16645930.

APA, 6th edition

La Revellière-Lépeaux, Louis-Marie de, 1753-1824. (["Box 5, folder 156"])(n.d.)[Seven sketches of Celtic monuments, accompanied by explanatory notes in pencil]. https://collections.library.yale.edu/catalog/16645930.