Khoekhoe language
Haacke, Wilfrid; Eiseb, Eliphas and Namaseb, Levi. 1997. "Internal and External Relations of Khoekhoe Dialects: A Preliminary Survey". In Wilfrid Haacke & Edward D. Elderkin, eds., Namibian Languages: Reports and Papers, 125–209. Cologne: Rüdiger Köppe Verlag for the University of Namibia.