MLA

Speck, William A. (William Alfred), 1864-1928. Kerker. Box 19. circa 1750-1850. https://collections.library.yale.edu/catalog/33076384.

APA, 6th edition

Speck, William A. (William Alfred), 1864-1928. (["Box 19"])(circa 1750-1850)[Kerker]. https://collections.library.yale.edu/catalog/33076384.