Não informado. (1954). Virginia minerals. Department of Conservation and Development, Division of Geology.
শিকাগো স্টাইল (17 তম সংস্করণ) উদ্ধৃতিNão informado. Virginia Minerals. Charlottesville, Va: Department of Conservation and Development, Division of Geology, 1954.
M.L.A (8 ম সংস্করণ) উদ্ধৃতিNão informado. Virginia Minerals. Department of Conservation and Development, Division of Geology, 1954.
সতর্কবাণী: সাইটেশন সবসময় 100% নির্ভুল হতে পারে না.