The mineral industry of Pennsylvania in 1980William Kebblish, Robert J. Tuchman, United States. Bureau of Mines, Pennsylvania. Bureau of Topographic and Geologic Survey · First published 1982Open the Tome
The mineral industry of Pennsylvania in 1976William Kebblish, United States. Bureau of Mines, Pennsylvania. Bureau of Topographic and Geologic Survey · First published 1980Open the Tome
