1. W. R. Frazer:Phys. Rev., 115, 1763 (1959).
2. D. Cassel, M. Barton, R. Crittenden, V. Fitch andL. Leipttner: to be published. See also the Princeton University Ph. D. Thesis ofD. Cassel:Form Factor of the π-Meson (1954).
3. B. Maglić andG. Costa:Prospective pion-electron colliding beam experiments using K-shell of heavy atom as electron «Storage ring », to appear in. theProceedings of the International Conference on High-Energy Physics at Dubna (1964).
4. E. Herman andR. Hofstadter:High-Energy Electron Scattering Tables (Stanford, 1960), p. 62.
5. R. Williams, J. Rainwater andA. Pevsner:Phys. Rev.,101, 412 (1956);W. F. Baker, J. Rainwater andR. E. Williams:Phys. Rev.,112, 1763 (1958).