Hardenburg, W. E. (1912). The Putumayo: The devil's paradise. Travels in the peruvian Amazon region and an account of the atrocities committed upon the indians therein, together with extracts from the report of Sir Rogers Casement confirming the occurrences. T. Fisher Unwin.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Hardenburg, W. E. The Putumayo: The Devil's Paradise. Travels in the Peruvian Amazon Region and an Account of the Atrocities Committed upon the Indians Therein, Together with Extracts from the Report of Sir Rogers Casement Confirming the Occurrences. London, England, United Kingdom: T. Fisher Unwin, 1912.
توثيق جمعية اللغة المعاصرة MLA (الإصدار التاسع)Hardenburg, W. E. The Putumayo: The Devil's Paradise. Travels in the Peruvian Amazon Region and an Account of the Atrocities Committed upon the Indians Therein, Together with Extracts from the Report of Sir Rogers Casement Confirming the Occurrences. T. Fisher Unwin, 1912.