Barton, Nicholas H. “Multilocus Clines.”https://doi.org/10.2307/2408260__Evolution; International Journal of Organic Evolution. Society for the Study of Evolution, 1983.https://doi.org/10.2307/2408260 .

Barton, Nicholas H. “The Structure of the Hybrid Zone in Uroderma Bilobatum (Chiroptera: Phyllostomatidae).”https://doi.org/10.1111/j.1558-5646.1982.tb05452.x__Evolution. Wiley, 1982.https://doi.org/10.1111/j.1558-5646.1982.tb05452.x .

Barton, Nicholas H, and Godfrey Hewitt. “A Chromosomal Cline in the Grasshopper Podisma Pedestris.”https://doi.org/ 10.1111/j.1558-5646.1981.tb04966.x__Evolution; International Journal of Organic Evolution. Wiley-Blackwell, 1981.https://doi.org/ 10.1111/j.1558-5646.1981.tb04966.x .