Não informado. (2020). Press Bulletin. State of California, Department of Natural Resources, Division of Mines.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. Press Bulletin. San Francisco, Calif: State of California, Department of Natural Resources, Division of Mines, 2020.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. Press Bulletin. State of California, Department of Natural Resources, Division of Mines, 2020.
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