Wagner, Walter Richard, 1928-1974.

• Geology of Pennsylvania’s oil and gas / by W. R. Wagner and W. S. Lytle ; illustrations by Lillian Heeren and Albert Van Olden
• Geology of Pennsylvania’s oil and gas, by W. R. Wagner and W. S. Lytle. Illus. by Lillian Heeren and Albert Van Olden
• Greater Pittsburgh region revised surface structure and its relation to oil and gas fields / by Walter R. Wagner and William S. Lytle ; prepared by the Pennsylvania Geological Survey in cooperation with the United States Geological Survey
• Greater Pittsburgh region revised surface structure and its relation to oil and gas fields.