1. J. Chadwick and M. Goldhaber, Nature,135, 3402 (1935).
2. Tritium, Topical Collection of Translations [Russian translation], AINF 149 (II), Moscow, Press of the Central Scientific Research Institute of Atomic Information (1971), p. 25.
3. É. L. Andronikashvili, T. V. Tsetskhladze, and E. E. Timofeeva, in: Nuclear-Chemical Phenomena in Solids [in Russian], Metsniereba, Tbilisi (1968), p. 68.
4. F. Pretzel, J. Phys. Chem. Solids,19, No. 4, 325 (1962).
5. W. Doyle, D. Ingram, and M. Smitli, Phys. Rev. Letters,2, 497 (1959).