Poland, showing the Eighteenth Century Partitions; at its greatest extent, 1772: before the second partition of 1793: before the third partition of 1795.
MLA
Poland, Showing the Eighteenth Century Partitions; at Its Greatest Extent, 1772: before the Second Partition of 1793: before the Third Partition of 1795. S. Thorne Jr., 1939. https://collections.library.yale.edu/catalog/15826659.
APA, 6th edition
Poland, showing the Eighteenth Century Partitions; at its greatest extent, 1772: before the second partition of 1793: before the third partition of 1795. (1939). [Manuscript maps]. S. Thorne Jr., https://collections.library.yale.edu/catalog/15826659.