1. V. N. Kerr, F. N. Hayes, and E. C. Anderson, Rev. Sci. Instr.,33, 100, 1962.
2. K. L. Luke and CH'ien-Hsiang Wu, eds., Principles and Method of the Recording of Elementary Particles [Russian translation], IL, Moscow, 1963.
3. L. M. Kukushkin and A. M. Ratner, ZhTF28, 2, 345, 1958;28, 5, 1121, 1958.