Não informado. (2001). West Virginia geological survey. Virginia Geological Survey.
Chicago (17e ed.) BronvermeldingNão informado. West Virginia Geological Survey. Morgantown, Va: Virginia Geological Survey, 2001.
MLA (8e ed.) BronvermeldingNão informado. West Virginia Geological Survey. Virginia Geological Survey, 2001.
Let op: Deze citaties zijn niet altijd 100% accuraat.