APA

Department of Energy and Natural Resources. Geological Survey, . (1938). Illinois Petroleum. Urbana: Geological Survey.

Chicago

Department of Energy and Natural Resources. Geological Survey, . 1938. Illinois Petroleum. Urbana: Geological Survey.

Harvard

Department of Energy and Natural Resources. Geological Survey, . (1938). Illinois Petroleum. Urbana: Geological Survey.

MLA

Department of Energy and Natural Resources. Geological Survey, . Illinois Petroleum. Urbana: Geological Survey. 1938.