MLA

McNally, Rand, and Company. The Rand McNally New Commercial Atlas Map of Pennsylvania ; Pennsylvania Automobile Road Map. Rand McNally & Co., 1918. https://collections.library.yale.edu/catalog/15827670.

APA, 6th edition

McNally, R., & C. (1918). The Rand McNally new commercial atlas map of Pennsylvania ; Pennsylvania automobile road map. [Maps]. Rand McNally & Co., https://collections.library.yale.edu/catalog/15827670.