Hopkins, H. W., & Hopkins, G. M., Jr. (1870). Atlas of Delaware County, Pennsylvania: Comprehending 26 maps drawn from official records, private plans and deeds, surveys of the different county surveyors, Dr. Joshua W. Ash's map, the U.S Coast Survey, and actual surveys throughout the county. Philadelphia, PA: Hopkins.

Hopkins, Henry Whitmer, and Griffith Morgan Hopkins, Jr. Atlas of Delaware County, Pennsylvania: Comprehending 26 Maps Drawn From Official Records, Private Plans and Deeds, Surveys of the Different County Surveyors, Dr. Joshua W. Ash's Map, the U.S Coast Survey, and Actual Surveys Throughout the County. Philadelphia, PA: Hopkins, 1870.

Hopkins, Henry Whitmer, and Griffith Morgan Hopkins, Jr. Atlas of Delaware County, Pennsylvania: Comprehending 26 Maps Drawn From Official Records, Private Plans and Deeds, Surveys of the Different County Surveyors, Dr. Joshua W. Ash's Map, the U.S Coast Survey, and Actual Surveys Throughout the County. Philadelphia, PA: Hopkins, 1870.