1. Vroom VH. Work and motivation. Wiley; 1964.
2. Donovan JJ. Work motivation. In: Anderson N, Ones DS, Sinangil HK, Viswesvaran C. Handbook of industrial, work and organizational psychology, Vol. 2. Organizational psychology. Sage;2002. pp. 53–76.
3. Miner JB. Organizational behavior 1: essential theories of motivation and leadership. Sharpe ME. 2005.
4. Tolman EC. Purposive behavior in animals and men. Century. 1932.
5. Tolman EC. Principles of purposive behavior. In: Koch S. Psychology: a study of a science (Vol. 2). McGraw-Hill; 1959. pp. 92–157.