Barton, Nicholas H. “Multilocus Clines.”10.2307/2408260__Evolution; International Journal of Organic Evolution, vol. 37, no. 3, Society for the Study of Evolution, 1983, pp. 454–71, doi:10.2307/2408260.

Barton, Nicholas H. “The Structure of the Hybrid Zone in Uroderma Bilobatum (Chiroptera: Phyllostomatidae).”10.1111/j.1558-5646.1982.tb05452.x__Evolution, vol. 36, no. 4, Wiley, 1982, pp. 863–66, doi:10.1111/j.1558-5646.1982.tb05452.x.

Barton, Nicholas H., and Godfrey Hewitt. “A Chromosomal Cline in the Grasshopper Podisma Pedestris.” 10.1111/j.1558-5646.1981.tb04966.x__Evolution; International Journal of Organic Evolution, vol. 35, no. 5, Wiley-Blackwell, 1981, pp. 1008–18, doi: 10.1111/j.1558-5646.1981.tb04966.x.