Oil and gas developments in Pennsylvania in 1970 /

অনুযায়ী Lytle, William S., Heyman, Louis, Kelley, Dana R.
Harrisburg, Pa : Pennsylvania, Bureau of Topographic and Geological Survey, 1971

Oil and gas developments in Pennsylvania in 1982 /

Harrisburg, Pa. : Pennsylvania, Bureau of Topographic and Geological Survey, 1983

Oil and gas developments in Pennsylvania in 1978 /

অনুযায়ী Piotrowski, Robert G.
Harrisburg, Pa. : Pennsylvania, Bureau of Topographic and Geological Survey, 1979

Oil and gas developments in Pennsylvania in 1977 /

অনুযায়ী Heyman, Louis, Cozart, Cheryl L.
Harrisburg, Pa. : Pennsylvania, Bureau of Topographic and Geological Survey, 1978

Oil and gas developments in Pennsylvania in 1964 /

অনুযায়ী Lytle, William S.
Harrisburg, PA. : Pennsylvania, Bureau of Topographic and Geologic Survey, 1965