Não informado. (2001). West Virginia geological survey. Virginia Geological Survey.
Chicagoスタイル(17版)引用形式Não informado. West Virginia Geological Survey. Morgantown, Va: Virginia Geological Survey, 2001.
MLA(8版)引用形式Não informado. West Virginia Geological Survey. Virginia Geological Survey, 2001.
警告: この引用は必ずしも正確ではありません.