APA   Click to copy
Li, I., Dey, A. K., & Forlizzi, J. (2011). Using context to reveal factors that affect physical activity.

Chicago/Turabian   Click to copy
Li, Ian, Anind K. Dey, and Jodi Forlizzi. “Using Context to Reveal Factors That Affect Physical Activity” (November 31, 2011).

MLA   Click to copy
Li, Ian, et al. Using Context to Reveal Factors That Affect Physical Activity. Nov. 2011.

@article{ian2011a,
  title = {Using context to reveal factors that affect physical activity},
  year = {2011},
  month = nov,
  day = {31},
  author = {Li, Ian and Dey, Anind K. and Forlizzi, Jodi},
  month_numeric = {11}
}