Paul Guinness; Brenda Walpole. (2012). Environmental Systems and Societies for the IB Diploma. CAMBRIDGE UNIVERSITY PRESS.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रPaul Guinness; Brenda Walpole. Environmental Systems and Societies for the IB Diploma. CAMBRIDGE UNIVERSITY PRESS, 2012.
एमएलए (9वां संस्करण) प्रशस्ति पत्रPaul Guinness; Brenda Walpole. Environmental Systems and Societies for the IB Diploma. CAMBRIDGE UNIVERSITY PRESS, 2012.
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