@inbook{10899,
  author       = {Barton, Nicholas H},
  booktitle    = {Encyclopedia of Biodiversity},
  isbn         = {978-0-12-384720-1},
  keywords     = {Adaptive landscape, Cline, Coalescent process, Gene flow, Hybrid zone, Local adaptation, Natural selection, Neutral theory, Population structure, Speciation},
  pages        = {508--515},
  publisher    = {Elsevier},
  title        = {{Differentiation}},
  doi          = {10.1016/b978-0-12-384719-5.00031-9},
  year         = {2013},
}