Não informado. (2009). Annual Report of the Geological Survey of Arkansas. Geological Survey of Arkansas.
Chicago-Zitierstil (17. Ausg.)Não informado. Annual Report of the Geological Survey of Arkansas. Little Rock, Ark: Geological Survey of Arkansas, 2009.
MLA-Zitierstil (8. Ausg.)Não informado. Annual Report of the Geological Survey of Arkansas. Geological Survey of Arkansas, 2009.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.