共 12 条
[2]
[Anonymous], R3568NIH RAND CORP
[3]
[Anonymous], NIH PUBLICATION
[4]
Arora A., 2005, Annals of Economics and Statistics / Annales d'conomie et de Statistiaue, P91, DOI 10.2307/20777571
[9]
Kaiser J, 2008, SCIENCE, V322, P358, DOI 10.1126/science.322.5900.358b
[10]
STEPHAN P, 1989, RES HIGH EDUC, V30, P531