J. F. Kelly, M Owen, Robert Bradley, Marion O'Brien, S Campbell, C. Brownell, K. McCartney, K. A. Clarke-Stewart, A Huston, D.L. Vandell, R. Pianta, M. Burchinal, C. Booth-LaForce, S. Spieker, M Cox, Marsha Weinraub, Bonnie Knoke, Jay Belsky, S.L. Friedman,
Child-care effect sizes for the NICHD Study of Early Child Care and Youth Development American Psychologist. ,vol. 61, pp. 99- 116 ,(2006)