MLA

Davidson, George, 1825-1911. Map showing routes from San Francisco to Alaska and the Klondike / compiled by Geo. Davidson.. BRBL_00635. c1897.. https://collections.library.yale.edu/catalog/15821792.

APA, 6th edition

Davidson, George, 1825-1911. (["BRBL_00635"])(c1897.)[Map showing routes from San Francisco to Alaska and the Klondike / compiled by Geo. Davidson.]. https://collections.library.yale.edu/catalog/15821792.