Sheafer, A. W., & Ashburner, C. A. (1885). The township geology of Elk and Forest counties. Board of Commissioners for the Second Geological Survey of Pennsylvania.
Chicago-Zitierstil (17. Ausg.)Sheafer, Arthur W., und Charles A. Ashburner. The Township Geology of Elk and Forest Counties. Harrisburg: Board of Commissioners for the Second Geological Survey of Pennsylvania, 1885.
MLA-Zitierstil (9. Ausg.)Sheafer, Arthur W., und Charles A. Ashburner. The Township Geology of Elk and Forest Counties. Board of Commissioners for the Second Geological Survey of Pennsylvania, 1885.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.