Dyfyniad APA

Lewis, R. S. (1939). Mining, the priceless heritage. Extension Division, University of Utah.

Dyfyniad Arddull Chicago

Lewis, Robert S. Mining, the Priceless Heritage. Salt Lake City: Extension Division, University of Utah, 1939.

Dyfyniad MLA

Lewis, Robert S. Mining, the Priceless Heritage. Extension Division, University of Utah, 1939.

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