1. Bennis, W., and Shepard, H.: A theory of group development. Human Relations, 9: 415–437, 1956.
2. Bion, W. R.: Experiences in Groups. Basic Books. New York. 1959.
3. Cartwright, D., and Zander, A.: Group Dynamics. Harper and Row. New York. 1968.
4. Selected Reading Series;G. L. Lippitt,1961
5. Merton, R. K.: Social Theory and Social Structure, Free Press. Glencoe, Ill. 1957.