1. J. L. Anderson,Quantization of General Relativity, Gravitation and Relativity, (W. A. Benjamin Inc., New York 1964), Chapter 14.
2. H. Arp,Observational paradoxes in extraterrestrial astronomy, Science174 (1971), 1189.
3. L. Eckhart,Four-Dimensional Space (Indiana University Press, 1968).
4. A. Einstein,Principle of Relativity (Dover Publications, New York 1923);The Meaning of Relativity (Princeton University Press, 1955).
5. A. Land�,New Foundation of Quantum Mechanics (Cambridge University Press, London 1965).