APA   Click to copy
Hsieh, G., Kraut, R. E., & Hudson, S. E. (2010). Why pay?: exploring how financial incentives are used for question & answer. Human Factors in Computing Systems, 305–314.

Chicago/Turabian   Click to copy
Hsieh, Gary, Robert E. Kraut, and Scott E. Hudson. “Why Pay?: Exploring How Financial Incentives Are Used for Question &Amp; Answer.” Human Factors in Computing Systems (March 9, 2010): 305–314.

MLA   Click to copy
Hsieh, Gary, et al. “Why Pay?: Exploring How Financial Incentives Are Used for Question &Amp; Answer.” Human Factors in Computing Systems, Mar. 2010, pp. 305–14.

@article{gary2010a,
  title = {Why pay?: exploring how financial incentives are used for question & answer},
  year = {2010},
  month = mar,
  day = {9},
  journal = {Human Factors in Computing Systems},
  pages = {305-314},
  author = {Hsieh, Gary and Kraut, Robert E. and Hudson, Scott E.},
  booktitle = {chi},
  month_numeric = {3}
}