MLA

Clésinger-Sand, Solange, 1828-1899. Rondier, ----. Box 2, folder 53. 1894 February 2. https://collections.library.yale.edu/catalog/17444485.

APA, 6th edition

Clésinger-Sand, Solange, 1828-1899. (["Box 2, folder 53"])(1894 February 2)[Rondier, ----]. https://collections.library.yale.edu/catalog/17444485.