Não informado. (1954). Virginia minerals. Department of Conservation and Development, Division of Geology.
Chicagoスタイル(17版)引用形式Não informado. Virginia Minerals. Charlottesville, Va: Department of Conservation and Development, Division of Geology, 1954.
MLA(8版)引用形式Não informado. Virginia Minerals. Department of Conservation and Development, Division of Geology, 1954.
警告: この引用は必ずしも正確ではありません.