APA   Click to copy
Colwell, R. K., & Rangel, T. F. (2009). Hutchinson's duality: the once and future niche. Proceedings of the National Academy of Sciences, 106, 19651–19658.

Chicago/Turabian   Click to copy
Colwell, Robert K, and Thiago F Rangel. “Hutchinson's Duality: the Once and Future Niche.” Proceedings of the National Academy of Sciences 106 (2009): 19651–19658.

MLA   Click to copy
Colwell, Robert K., and Thiago F. Rangel. “Hutchinson's Duality: the Once and Future Niche.” Proceedings of the National Academy of Sciences, vol. 106, National Academy of Sciences, 2009, pp. 19651–58.

@article{colwell2009a,
  title = {Hutchinson's duality: the once and future niche},
  year = {2009},
  journal = {Proceedings of the National Academy of Sciences},
  pages = {19651--19658},
  publisher = {National Academy of Sciences},
  volume = {106},
  author = {Colwell, Robert K and Rangel, Thiago F}
}