Coal resources of Lawrence County, Pennsylvania /

by Van Lieu, J. A.
Washington, [D.C.] : U.S. G.P.O., 1964

The publications of the Second Geological Survey of Pennsylvania : from 1874 to 1884.

[Philadelphia, Pa.] : [Board of Commissioners for the Second Geological Survey of Pennsylvania], 1884

Coal resources of Butler County, Pennsylvania /

by Patterson, E. D. (Elmer Davisson), Van Lieu, J. A.
Washington : U.S. Govt. Print. Off, 1971