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3. Tuve, M. A., Heÿdenburg, N. P., and Hafstad, L. R., Phys. Rev., 50, 806 (1936); Breit, G., Condon, E. U., and Present, R. D., Phys. Rev., 50, 825 (1936).
4. Bethe, H. A., "Nuclear Physics". Rev. Mod. Phys. Part A (with R. F. Bacher ), 8, 82; Part B, 9, 71; Part C (with M. S. Livingston ), 9, 245. See especially Part B, formula (598), p. 166.