MLA

The Russian Discoveries from the Map Published by the Imperial Academy of St. Petersburg. London, Printed for Robt. Sayer ... the Imperial Academy of St. Petersburg, 1775. https://collections.library.yale.edu/catalog/15235135.

APA, 6th edition

The Russian discoveries from the map published by the Imperial Academy of St. Petersburg. London, Printed for Robt. Sayer ... (1775). [Maps]. the Imperial Academy of St. Petersburg, https://collections.library.yale.edu/catalog/15235135.