Perman, R. (2011). Natural resource and environmental economics. Harlow, Essex: Pearson Addison Wesley.
शिकागो स्टाइल उद्धरणPerman, Roger. Natural Resource and Environmental Economics. Harlow, Essex: Pearson Addison Wesley, 2011.
एमएलए उद्धरणPerman, Roger. Natural Resource and Environmental Economics. Harlow, Essex: Pearson Addison Wesley, 2011.
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