1. : Frames of Mind, Basic Books, New York 1983.
2. (a) : Structural Stability and Morphogenesis. Benjamin, New York 1975, p. 11;
3. (b) Structural Stability and Morphogenesis. Benjamin, New York 1975 p. 5;
4. (c) Structural Stability and Morphogenesis. Benjamin, New York 1975 p. 6.