Não informado. (1954). Virginia minerals. Department of Conservation and Development, Division of Geology.
Style de citation Chicago (17e éd.)Não informado. Virginia Minerals. Charlottesville, Va: Department of Conservation and Development, Division of Geology, 1954.
Style de citation MLA (8e éd.)Não informado. Virginia Minerals. Department of Conservation and Development, Division of Geology, 1954.
Attention : ces citations peuvent ne pas être correctes à 100%.