MLA

Scull, William, active 1765, cartographer. A map of Pennsylvania exhibiting not only the improved parts of that Province, but also its extensive frontiers: Laid down from actual surveys, and chiefly from the late map of W. Scull published in 1770; and humbly inscribed to the Honorable Thomas Penn. BRBL_00730. 10 June 1775.. https://collections.library.yale.edu/catalog/15830798.

APA, 6th edition

Scull, William, active 1765, cartographer. (["BRBL_00730"])(10 June 1775.)[A map of Pennsylvania exhibiting not only the improved parts of that Province, but also its extensive frontiers: Laid down from actual surveys, and chiefly from the late map of W. Scull published in 1770; and humbly inscribed to the Honorable Thomas Penn]. https://collections.library.yale.edu/catalog/15830798.