APA   Click to copy
Ariew, A., & Ernst, Z. (2009). What fitness can’t be. Erkenntnis, 71, 289–301. https://doi.org/10.1007/s10670-009-9183-9

Chicago/Turabian   Click to copy
Ariew, André, and Zachary Ernst. “What Fitness Can’t Be.” Erkenntnis 71 (2009): 289–301.

MLA   Click to copy
Ariew, André, and Zachary Ernst. “What Fitness Can’t Be.” Erkenntnis, vol. 71, 2009, pp. 289–301, doi:10.1007/s10670-009-9183-9.

@article{andr2009a,
  title = {What fitness can’t be},
  year = {2009},
  journal = {Erkenntnis},
  pages = {289--301},
  volume = {71},
  doi = {10.1007/s10670-009-9183-9},
  author = {Ariew, André and Ernst, Zachary}
}