MLA

Gray, W. Vallance, and C. B. Gifford. Bird's Eye View of the City & County of San Francisco, 1868 [Cartographic Material]. American West, 1868. https://collections.library.yale.edu/catalog/2016104.

APA, 6th edition

Gray, W. V., & Gifford, C. B. (1868). Bird's eye view of the city & county of San Francisco, 1868 [cartographic material]. [Aerial views]. American West. https://collections.library.yale.edu/catalog/2016104.