MLA

Clésinger-Sand, Solange, 1828-1899. Gaubert, Marie. Box 1, folder 29. 1897-1898. https://collections.library.yale.edu/catalog/17444463.

APA, 6th edition

Clésinger-Sand, Solange, 1828-1899. (["Box 1, folder 29"])(1897-1898)[Gaubert, Marie]. https://collections.library.yale.edu/catalog/17444463.