APA
Miao Q., National Bureau of Economic Research & Popp D. (2013). Necessity as the mother of invention. Cambridge: NBER.
Chicago
Miao Qing, National Bureau of Economic Research and Popp David. 2013. Necessity as the mother of invention. Cambridge: NBER.
Harvard
Miao Q., National Bureau of Economic Research and Popp D. (2013). Necessity as the mother of invention. Cambridge: NBER.
MLA
Miao Qing, National Bureau of Economic Research and Popp David. Necessity as the mother of invention. Cambridge: NBER. 2013.