MLA

Hawthorne, Nathaniel, 1804-1864. Winthrop, Robert [Charles?]. Box 2, folder 55. 1864 Feb 15. https://collections.library.yale.edu/catalog/2064570.

APA, 6th edition

Hawthorne, Nathaniel, 1804-1864. (["Box 2, folder 55"])(1864 Feb 15)[Winthrop, Robert [Charles?]]. https://collections.library.yale.edu/catalog/2064570.