International Progress Organization, Köchler, H., & Grabher, G. (1999). Civilizations: Conflict or dialogue. International Progress Organization.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रInternational Progress Organization, Hans Köchler, और Gudrun Grabher. Civilizations: Conflict or Dialogue. Vienna, Austria: International Progress Organization, 1999.
एमएलए (9वां संस्करण) प्रशस्ति पत्रInternational Progress Organization, et al. Civilizations: Conflict or Dialogue. International Progress Organization, 1999.
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