Não informado. Oil and Gas Investigations. State Geological Survey.
Chicago-Zitierstil (17. Ausg.)Não informado. Oil and Gas Investigations. Lawrence, Kan: State Geological Survey.
MLA-Zitierstil (8. Ausg.)Não informado. Oil and Gas Investigations. State Geological Survey.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.