MLA

A Map of the Country Round Philadelphia : Including Part of New Jersey, New York, Staten Island & Long Island. Gentleman's magazine, 1776. https://collections.library.yale.edu/catalog/15830775.

APA, 6th edition

A map of the country round Philadelphia : including part of New Jersey, New York, Staten Island & Long Island. (1776). [Maps]. Gentleman's magazine, https://collections.library.yale.edu/catalog/15830775.