Altruism may arise from individual selection.

MLA

Sánchez, Angel, and José A. Cuesta. “Altruism May Arise from Individual Selection.” Journal of Theoretical Biology, vol. 235, no. 2, July 2005, pp. 233–40. EBSCOhost, https://doi.org/10.1016/j.jtbi.2005.01.006.

APA

Sánchez, A., & Cuesta, J. A. (2005). Altruism may arise from individual selection. Journal of Theoretical Biology, 235(2), 233–240. https://doi.org/10.1016/j.jtbi.2005.01.006

Chicago

Sánchez, Angel, and José A Cuesta. 2005. “Altruism May Arise from Individual Selection.” Journal of Theoretical Biology 235 (2): 233–40. doi:10.1016/j.jtbi.2005.01.006.