International Progress Organization, Köchler, H., & Grabher, G. (1999). Civilizations: Conflict or dialogue. International Progress Organization.
Chicago-referens (17:e uppl.)International Progress Organization, Hans Köchler, och Gudrun Grabher. Civilizations: Conflict or Dialogue. Vienna, Austria: International Progress Organization, 1999.
MLA-referens (9:e uppl.)International Progress Organization, et al. Civilizations: Conflict or Dialogue. International Progress Organization, 1999.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.