O'Harra, C. C. (1899). Notes on the geology and mineral deposits of a portion of the southern Black Hills. South Dakota School of Mines.
Chicago-viite (17. p.)O'Harra, Cleophas C. Notes on the Geology and Mineral Deposits of a Portion of the Southern Black Hills. Rapid City, S. D.: South Dakota School of Mines, 1899.
MLA-viite (8. p.)O'Harra, Cleophas C. Notes on the Geology and Mineral Deposits of a Portion of the Southern Black Hills. South Dakota School of Mines, 1899.
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