Comas, D., Calafell, F., Benchemsi, N., Helal, A., Lefranc, G., Stoneking, M., et al. (2000). Alu insertion polymorphisms in Northwest Africa and the Iberian Peninsula: Evidence for a strong genetic boundary through the Gibraltar Straits. Human Genetics, 107(4), 312-319. doi:10.1007/s004390000370.