(1969). Geologic map and sections of parts of the Portland and Belvidere quadrangles New Jersey-Pennsylvania. U.S. Geological Survey.
Chicago-Zitierstil (17. Ausg.)Geologic Map and Sections of Parts of the Portland and Belvidere Quadrangles New Jersey-Pennsylvania. Washington, D.C: U.S. Geological Survey, 1969.
MLA-Zitierstil (9. Ausg.)Geologic Map and Sections of Parts of the Portland and Belvidere Quadrangles New Jersey-Pennsylvania. U.S. Geological Survey, 1969.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.