MLA

Mitchell, S. Weir (Silas Weir), 1829-1914. Letters : 1524 Walnut Street, Philadelphia. Box 8, folder GROUP 156, F-10. [1896]-1905. https://collections.library.yale.edu/catalog/10081321.

APA, 6th edition

Mitchell, S. Weir (Silas Weir), 1829-1914. (["Box 8, folder GROUP 156, F-10"])([1896]-1905)[Letters : 1524 Walnut Street, Philadelphia]. https://collections.library.yale.edu/catalog/10081321.