Wang PS, et al. “Making the Business Case for Enhanced Depression Care: The National Institute of Mental Health–Harvard Work Outcomes Research and Cost-Effectiveness Study,” Journal of Occupational and Environmental Medicine (April 2008): Vol. 50, No. 4, pp. 468–75.
 Kessler RC et al: Prevalence and Effects of Mood Disorders on Work Performance in a Nationally Representative Sample of U.S. Workers. American Journal of Psychiatry, Sept. 2006, pp. 1561-1568.
 Loeppke R, et al. “Health and Productivity as a Business Strategy: A Multiemployer Study,” Journal of Occupational and Environmental Medicine (April 2009): Vol. 51, No. 4, pp. 411–28.