Não informado. (2009). Annual Report of the Geological Survey of Arkansas. Geological Survey of Arkansas.
Chicago (17e ed.) BronvermeldingNão informado. Annual Report of the Geological Survey of Arkansas. Little Rock, Ark: Geological Survey of Arkansas, 2009.
MLA (8e ed.) BronvermeldingNão informado. Annual Report of the Geological Survey of Arkansas. Geological Survey of Arkansas, 2009.
Let op: Deze citaties zijn niet altijd 100% accuraat.