Güldemann, Tom (2018). 〈Historical linguistics and genealogical language classification in Africa〉. Güldemann, Tom (편집). 《The Languages and Linguistics of Africa》. The World of Linguistics series 11. Berlin: De Gruyter Mouton. 58–444쪽. doi:10.1515/9783110421668-002. ISBN978-3-11-042606-9.
Hammarström, Harald; Forkel, Robert; Haspelmath, Martin; Bank, Sebastian 편집 (2023). 〈Khoe–Kwadi〉 (영어). 《Glottolog 4.8》 [글로톨로그 4.8]. Jena, Germany: Max Planck Institute for the Science of Human History.