MLA

Colton, G. Woolworth (George Woolworth), 1827-1901. Colton's county and township rail road map of Wisconsin, Illinois, Missouri, & Iowa / Drawn, engraved & published by G. Woolworth Colton. BRBL_00420. 1862. https://collections.library.yale.edu/catalog/15604000.

APA, 6th edition

Colton, G. Woolworth (George Woolworth), 1827-1901. (["BRBL_00420"])(1862)[Colton's county and township rail road map of Wisconsin, Illinois, Missouri, & Iowa / Drawn, engraved & published by G. Woolworth Colton]. https://collections.library.yale.edu/catalog/15604000.