Não informado. (1954). Virginia minerals. Department of Conservation and Development, Division of Geology.
Chicago-Zitierstil (17. Ausg.)Não informado. Virginia Minerals. Charlottesville, Va: Department of Conservation and Development, Division of Geology, 1954.
MLA-Zitierstil (8. Ausg.)Não informado. Virginia Minerals. Department of Conservation and Development, Division of Geology, 1954.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.