MLA

Pratt, Richard Henry, 1840-1924. Miscellaneous papers, 10 items. Box 14, folder 490. 1875 May. https://collections.library.yale.edu/catalog/17104179.

APA, 6th edition

Pratt, Richard Henry, 1840-1924. (["Box 14, folder 490"])(1875 May)[Miscellaneous papers, 10 items]. https://collections.library.yale.edu/catalog/17104179.