作者:ICHNIOWSKI, C; FREEMAN, RB; LAUER, H
作者单位:National Bureau of Economic Research; Harvard University
作者:KOSTIUK, PF; FOLLMANN, DA
作者单位:National Institutes of Health (NIH) - USA; NIH National Heart Lung & Blood Institute (NHLBI)
作者:SMITH, BD
作者单位:University of Rochester