MLA

Clésinger-Sand, Solange, 1828-1899. Bourdet, Édouard. Box 1, folder 10. 1851 November 10. https://collections.library.yale.edu/catalog/17444449.

APA, 6th edition

Clésinger-Sand, Solange, 1828-1899. (["Box 1, folder 10"])(1851 November 10)[Bourdet, Édouard]. https://collections.library.yale.edu/catalog/17444449.