Ackerman, P. L.; Kanfer, R. (1989). "Motivation and cognitive abilities: An integrative/aptitude-treatment interaction approach to skill acquisition". Journal of Applied Psychology. 74 (4): 657–690. doi:10.1037/0021-9010.74.4.657.
Ackerman, Phillip L. (1996). "A theory of adult intellectual development: Process, personality, interests, and knowledge". Intelligence. 22 (2): 227–257. doi:10.1016/S0160-2896(96)90016-1.