1. Gallagher James J., Teaching Gifted Students (Boston, Allyn and Bacon, 1965), p. 236.
2. Skinner B. F., The Technology of Teaching (New York, Meredith Corporation, 1968), p. 9.
3. Three faces of intellect.
4. Bruner J., Toward a Theory of Instruction (New York, W. W. Norton and Co., Inc., 1968), p. 127.