Não informado. (2009). Occasional Publications of the Department of Geography. University of Illinois at Urbana-Champaign.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNão informado. Occasional Publications of the Department of Geography. Urbana, Ill: University of Illinois at Urbana-Champaign, 2009.
एमएलए (8वां संस्करण) प्रशस्ति पत्रNão informado. Occasional Publications of the Department of Geography. University of Illinois at Urbana-Champaign, 2009.
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