Cite

2 ALS and 4 TLS to Mr. Manning, Mount Vernon, N. Y. [etc.]

MLA

Book, Beinecke Rare, and Manuscript Library. Collection of American Literature. 2 ALS and 4 TLS to Mr. Manning, Mount Vernon, N. Y. [Etc.]. 1904. https://collections.library.yale.edu/catalog/2005122.

APA, 6th edition

Book, B. R., & of American Literature, M. L. C. (1904). 2 ALS and 4 TLS to Mr. Manning, Mount Vernon, N. Y. [etc.]. https://collections.library.yale.edu/catalog/2005122.