MLA

Allen, Willian A. Map of the Railroads of the State of Maine : Accompanying the Report of the Railroad Commissioners. Railroad Commissioners, 1895. https://collections.library.yale.edu/catalog/15607020.

APA, 6th edition

Allen, W. A. (1895). Map of the railroads of the state of Maine : accompanying the report of the Railroad Commissioners. [Maps]. Railroad Commissioners, https://collections.library.yale.edu/catalog/15607020.