Ashburner, C. A. (1880). The Geology of McKean County, and its connection with that of Cameron, Elk and Forest. Board of Commissioners for the Second Geological Survey of Pennsylvania.
Chicago-Zitierstil (17. Ausg.)Ashburner, Charles A. The Geology of McKean County, and Its Connection with That of Cameron, Elk and Forest. Harrisburg: Board of Commissioners for the Second Geological Survey of Pennsylvania, 1880.
MLA-Zitierstil (9. Ausg.)Ashburner, Charles A. The Geology of McKean County, and Its Connection with That of Cameron, Elk and Forest. Board of Commissioners for the Second Geological Survey of Pennsylvania, 1880.
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