Speth, J. G. (2004). Global environmental challenges: Transitions to a sustainable world. Orient Longman.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रSpeth, James Gustave. Global Environmental Challenges: Transitions to a Sustainable World. Orient Longman, 2004.
एमएलए (9वां संस्करण) प्रशस्ति पत्रSpeth, James Gustave. Global Environmental Challenges: Transitions to a Sustainable World. Orient Longman, 2004.
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