Theodore W. Schultz, 1981.Investing in People. p. 3. University of California Press.
doi.org
Burnett, Paul (2011). "Academic Freedom or Political Maneuvers: Theodore W. Schultz and the Oleomargarine Controversy Revisited". Agricultural History. 85 (3): 373–397. doi:10.3098/ah.2011.85.3.373. PMID21901904.
Burnett, Paul (2011). "Academic Freedom or Political Maneuvers: Theodore W. Schultz and the Oleomargarine Controversy Revisited". Agricultural History. 85 (3): 373–397. doi:10.3098/ah.2011.85.3.373. PMID21901904.