Divergent selection on bill morphology contributes to nonrandom mating between swamp sparrow subspeciesDOI: info:10.1016/j.anbehav.2013.06.002v. 86No. 2Elsevier467–473
Ballentine, Barbara, Horton, Brent, Brown, E. T., and Greenberg, Russell S. 2013. "Divergent selection on bill morphology contributes to nonrandom mating between swamp sparrow subspecies." Animal Behaviour, 86, (2) 467–473. https://doi.org/10.1016/j.anbehav.2013.06.002.