Elliot, Sam (March 21, 2012). "Ten Days in Africa". earthship.com. Earthship Biotecture. Archived from the original on 30 October 2012. Retrieved 14 May 2013.
Elliot, Sam (March 21, 2012). "Ten Days in Africa". earthship.com. Earthship Biotecture. Archived from the original on 30 October 2012. Retrieved 14 May 2013.
McHenry, Paul Graham. (1989) [1984]. Adobe and rammed earth buildings : design and construction. Tucson: University of Arizona Press. ISBN0816511241. OCLC19849881.