1. N. Bohr to Y. Nishina (January 26, 1934), inY Nishina's Correspondence with N. Bohr and Copenhageners, 1928-1949 (Tokyo: Nishina Memorial Foundation,1984), pp.31-33on p. 31.
2. Y. Nishina to N. Bohr (October 21, 1928), inY. Nishina's Letters to N. Bohr, G. Hevesy and Others, 1923-1928 (Tokyo: Nishina Memorial Foundation,1985), pp.23-24on p. 23.