Dupree, W. G. (1972). United States Energy Through the Year 2000. Washington: U.S. Department of teh Interior.
शिकागो स्टाइल उद्धरणDupree, Walter G. United States Energy Through the Year 2000. Washington: U.S. Department of teh Interior, 1972.
एमएलए उद्धरणDupree, Walter G. United States Energy Through the Year 2000. Washington: U.S. Department of teh Interior, 1972.
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