APA
Nunn N., Qian Nancy & National Bureau Of Economic Research. (2009). The potato's contribution to population and urbanization: E. Cambridge: NBER.
Chicago
Nunn Nathan, Qian Nancy and National Bureau Of Economic Research. 2009. The potato's contribution to population and urbanization: E. Cambridge: NBER.
Harvard
Nunn N., Qian Nancy and National Bureau Of Economic Research. (2009). The potato's contribution to population and urbanization: E. Cambridge: NBER.
MLA
Nunn Nathan, Qian Nancy and National Bureau Of Economic Research. The potato's contribution to population and urbanization: E. Cambridge: NBER. 2009.
