1. Adams, D. A. (1975). Patented device reported in ?The Amateur Scientist,?Scientific American,Dec., 120.
2. Bolker, E. D. (1973). ?The Spinor Spanner,?American Mathematical Monthly,Nov., 977.
3. Clifford, W. K. (1956). ?On the Space Theory of Matter,?The World of Mathematics, Vol. 1, Ed. J. R. Newman, (Simon & Schuster, New York), p. 568.
4. McConnell, J. (1960).Quantum Particle Dynamics, 2nd Edn. (North-Holland, New York), pp 116 ff.
5. Rebbi, C. (1979). ?Solitons,?Scientific American,Feb., 92, 168.