Güldemann, Tom (2018). «Historical linguistics and genealogical language classification in Africa». En Güldemann, Tom, ed. The Languages and Linguistics of Africa. The World of Linguistics series 11. Berlin: De Gruyter Mouton. pp. 58-444. ISBN978-3-11-042606-9. S2CID133888593. doi:10.1515/9783110421668-002.
Güldemann, Tom (2018). «Historical linguistics and genealogical language classification in Africa». En Güldemann, Tom, ed. The Languages and Linguistics of Africa. The World of Linguistics series 11. Berlin: De Gruyter Mouton. pp. 58-444. ISBN978-3-11-042606-9. S2CID133888593. doi:10.1515/9783110421668-002.