1. M. Froissart:Phys. Rev.,123, 1053 (1961).
2. A. Martin:Phys. Rev.,129, 1432 (1963);Y. S. Jin andA. Martin:Phys. Rev.,153, B 1375 (1964).
3. F. J. Yndurain:Absolute bounds on cross-sections at all energies and without unknown constants, to be published inPhys. Lett. The bound quoted here in (1.1) is actually an improvement on the bound given in the original version of the above paper. We would like to thank Dr.F. J. Yndurain for informing us of his new bound.
4. L. Łukaszuk andA. Martin:Nuovo Cimento,52 A, 122 (1967).
5. V. Singh andS. M. Roy:Upper bounds on the elastic differential cross-sections, preprint of the Tata Institute of Fundamental Research, Bombay.