MLA

Hunter, Mary Smyth, 1856-1933. Mancini, Antonio. Box 2, folder 45. 1902-1903, undated. https://collections.library.yale.edu/catalog/16831779.

APA, 6th edition

Hunter, Mary Smyth, 1856-1933. (["Box 2, folder 45"])(1902-1903, undated)[Mancini, Antonio]. https://collections.library.yale.edu/catalog/16831779.