1. See for instanceM. Verde:Helv. Phys. Acta,23, 453 (1950).
2. SeeR. S. Christian andJ. Gammel:Phys. Rev.,91, 100 (1953).
3. J. Irwing:Phil. Mag.,42, 338 (1953).
4. See for instance:L. Hulthén andM. Sugawara:Handb. d. Phys.,39 (Berlin, 1957).
5. M. Verde [see ref. (1), using a different tipe of wave function for the three bodies, obtained a much lower value for the maximum (which came out about 0.5 mbar for the same energy). This is a connection with the assumption of a smaller value for the size of the three-particle nuclei.