APA   Click to copy
Colwell, R. K., & Futuyma, D. J. (1971). On the measurement of niche breadth and overlap. Ecology, 52, 567–576.

Chicago/Turabian   Click to copy
Colwell, Robert K, and Douglas J Futuyma. “On the Measurement of Niche Breadth and Overlap.” Ecology 52 (1971): 567–576.

MLA   Click to copy
Colwell, Robert K., and Douglas J. Futuyma. “On the Measurement of Niche Breadth and Overlap.” Ecology, vol. 52, Ecological Society of America, 1971, pp. 567–76.

@article{colwell1971a,
  title = {On the measurement of niche breadth and overlap},
  year = {1971},
  journal = {Ecology},
  pages = {567--576},
  publisher = {Ecological Society of America},
  volume = {52},
  author = {Colwell, Robert K and Futuyma, Douglas J}
}