Lewis, R. S. (1939). Mining, the priceless heritage. Extension Division, University of Utah.
Chicagoスタイル(17版)引用形式Lewis, Robert S. Mining, the Priceless Heritage. Salt Lake City: Extension Division, University of Utah, 1939.
MLA(8版)引用形式Lewis, Robert S. Mining, the Priceless Heritage. Extension Division, University of Utah, 1939.
警告: この引用は必ずしも正確ではありません.