Karin Holmgren; Helena Öberg «Climate Change in Southern and Eastern Africa during the past millennium and its implications for societal development». Environment, Development and Sustainability, 8, 2006, pàg. 1573–2975. DOI: 10.1007/s10668-005-5752-5.
Gilbert Pwiti «Economic change, ideology and the development of cultural complexity in northern Zimbabwe». Azania: Archaeological Research in Africa, 39, 2004, pàg. 265–282. DOI: 10.1080/00672700409480403.