Worldwatch Institute & Brown, L. R. (1999). State of the world 1999: A Worldwatch Institute report on progress toward a sustainable society. W. W. Norton & Company.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रWorldwatch Institute और Lester Russell Brown. State of the World 1999: A Worldwatch Institute Report on Progress Toward a Sustainable Society. New York ; London: W. W. Norton & Company, 1999.
एमएलए (8वां संस्करण) प्रशस्ति पत्रWorldwatch Institute और Lester Russell Brown. State of the World 1999: A Worldwatch Institute Report on Progress Toward a Sustainable Society. W. W. Norton & Company, 1999.
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