Não informado. (2009). Occasional Publications of the Department of Geography. University of Illinois at Urbana-Champaign.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Não informado. Occasional Publications of the Department of Geography. Urbana, Ill: University of Illinois at Urbana-Champaign, 2009.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)Não informado. Occasional Publications of the Department of Geography. University of Illinois at Urbana-Champaign, 2009.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.