Ohio State Map (Map). Cartography by Ohio Department of Highways and Public Works. Ohio Department of Highways and Public Works. July 1923. Archived from the original(MrSID) on November 2, 2013. Retrieved July 22, 2013.
Ohio State Map (Map). Cartography by Ohio Department of Highways and Public Works. Ohio Department of Highways and Public Works. August 1924. Archived from the original(MrSID) on October 7, 2013. Retrieved July 22, 2013.
Ohio State Map(JPG) (Map). Cartography by Ohio Department of Transportation. Ohio Department of Transportation. July 2011. ยง 4H. Retrieved July 22, 2013.
Ohio State Map (Map). Cartography by Ohio Department of Highways and Public Works. Ohio Department of Highways and Public Works. July 1923. Archived from the original(MrSID) on November 2, 2013. Retrieved July 22, 2013.
Ohio State Map (Map). Cartography by Ohio Department of Highways and Public Works. Ohio Department of Highways and Public Works. August 1924. Archived from the original(MrSID) on October 7, 2013. Retrieved July 22, 2013.