APA
Mark Ottoni-Wilhelm, National Bureau of Economic Research, Vesterlund L. & Xie H. (2014). Why do people give?. Cambridge: NBER.
Chicago
Mark Ottoni-Wilhelm, National Bureau of Economic Research, Vesterlund Lise and Xie Huan. 2014. Why do people give?. Cambridge: NBER.
Harvard
Mark Ottoni-Wilhelm, National Bureau of Economic Research, Vesterlund L. and Xie H. (2014). Why do people give?. Cambridge: NBER.
MLA
Mark Ottoni-Wilhelm, National Bureau of Economic Research, Vesterlund Lise and Xie Huan. Why do people give?. Cambridge: NBER. 2014.