APA   Click to copy
Salazar, D., & Marquis, R. J. (2012). Herbivore pressure increases toward the equator. Proceedings of the National Academy of Sciences, 109, 12616–12620.

Chicago/Turabian   Click to copy
Salazar, Diego, and Robert J Marquis. “Herbivore Pressure Increases toward the Equator.” Proceedings of the National Academy of Sciences 109 (2012): 12616–12620.

MLA   Click to copy
Salazar, Diego, and Robert J. Marquis. “Herbivore Pressure Increases toward the Equator.” Proceedings of the National Academy of Sciences, vol. 109, National Academy of Sciences USA, 2012, pp. 12616–20.

@article{salazar2012a,
  title = {Herbivore pressure increases toward the equator},
  year = {2012},
  journal = {Proceedings of the National Academy of Sciences},
  pages = {12616--12620},
  publisher = {National Academy of  Sciences USA},
  volume = {109},
  author = {Salazar, Diego and Marquis, Robert J}
}