N. H. Barton, “Multilocus clines,” Evolution; International Journal of Organic Evolution, vol. 37, no. 3. Society for the Study of Evolution, pp. 454–471, 1983.
LibreCat: https://research-explorer.ista.ac.at/record/3668
DOI: 10.2307/2408260
PMID: 28563316 

N. H. Barton, “The structure of the hybrid zone in Uroderma bilobatum (Chiroptera: Phyllostomatidae),” Evolution, vol. 36, no. 4. Wiley, pp. 863–866, 1982.
LibreCat: https://research-explorer.ista.ac.at/record/4331
DOI: 10.1111/j.1558-5646.1982.tb05452.x
PMID: 28568238

N. H. Barton and G. Hewitt, “A chromosomal cline in the grasshopper Podisma pedestris,” Evolution; International Journal of Organic Evolution, vol. 35, no. 5. Wiley-Blackwell, pp. 1008–1018, 1981.
LibreCat: https://research-explorer.ista.ac.at/record/3670
DOI:  10.1111/j.1558-5646.1981.tb04966.x
PMID: 28581059