APA
Colwell, R. K. (2000). A barrier runs through it… or maybe just a river. Proceedings of the National Academy of Sciences, 97, 13470–13472.
Chicago/Turabian
Colwell, Robert K. “A Barrier Runs through It… or Maybe Just a River.” Proceedings of the National Academy of Sciences 97 (2000): 13470–13472.
MLA
Colwell, Robert K. “A Barrier Runs through It… or Maybe Just a River.” Proceedings of the National Academy of Sciences, vol. 97, National Academy of Sciences, 2000, pp. 13470–72.