by Kenneth D. Woodruff ; sheet 3. -- Delaware Geological Survey, University of Delaware, 1984. -- (Hydrologic map series ; no. 3). a. -- 巻号等:sheet 3<図書>
by Kenneth D. Woodruff ; sheet 2. -- Delaware Geological Survey, University of Delaware, 1984. -- (Hydrologic map series ; no. 3). a. -- 巻号等:sheet 2<図書>