Não informado. (2009). Annual Report of the Geological Survey of Arkansas. Geological Survey of Arkansas.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. Annual Report of the Geological Survey of Arkansas. Little Rock, Ark: Geological Survey of Arkansas, 2009.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. Annual Report of the Geological Survey of Arkansas. Geological Survey of Arkansas, 2009.
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