1. Coal resources of Butler County, Pennsylvania / by Elmer D. Patterson and J.A. Van Lieu. Patterson, E. D. (Elmer Davisson) [Browse] Washington, D.C. : United States Department of the Interior, Geological Survey, 1971.Washington, D.C. : Government Printing Office. Book No holdings available for this record
2. Coal resources of Lawrence County, Pennsylvania / by J.A. Van Lieu and Elmer D. Patterson. Van Lieu, J. A. [Browse] Washington, D.C. : United States Department of the Interior, Geological Survey, 1964.Washington, D.C. : Government Printing Office. Book No holdings available for this record
3. Coal resources of Beaver County, Pennsylvania / by Elmer D. Patterson. Patterson, E. D. (Elmer Davisson) [Browse] Washington, D.C. : United States Department of the Interior, Geological Survey, 1963.Washington, D.C. : Government Printing Office. Book No holdings available for this record