ツウ語族
Güldemann, Tom. (2006). "The San languages of southern Namibia: Linguistic appraisal with special reference to J. G. Krönlein’s N|uusaa data." Anthropological Linguistics, 48(4): 369-395.
Story, Robert. (1999). "K'u|ha:si Manuscript" (MS collections of the Ki|hazi dialect of Bushman, 1937). Khoisan Forum Working Paper 13. ed. Anthony Traill. Köln: University of Köln. 18-34.