MLA

Denny, Edward, and Co. Denny's Pocket Map of Sacramento County, California / Compiled from Latest Official and Private Data by Edward Denny & Co. Edward Denny & Co., 0AD. https://collections.library.yale.edu/catalog/15818736.

APA, 6th edition

Denny, E., & C. (0 C.E.). Denny's pocket map of Sacramento County, California / compiled from latest official and private data by Edward Denny & Co. [Maps]. Edward Denny & Co., https://collections.library.yale.edu/catalog/15818736.