MLA

Clésinger-Sand, Solange, 1828-1899. Rocheblave, S. (Samuel). Box 2, folder 52. 1891-1898, undated. https://collections.library.yale.edu/catalog/17444484.

APA, 6th edition

Clésinger-Sand, Solange, 1828-1899. (["Box 2, folder 52"])(1891-1898, undated)[Rocheblave, S. (Samuel)]. https://collections.library.yale.edu/catalog/17444484.