1. W. Heitler, The Quantum Theory of Radiation, 3rd edn. (Oxford University Press, Oxford, 1954)
2. P.J. Black, P.B. Moon, Nature 188, 841 (1960)
3. S. Bernstein, E.C. Campbell, Phys. Rev. 132, 1625 (1963)
4. P.J. Black, I.P. Duerdoth, Proc. Phys. Soc. 84, 169 (1964)
5. G.T. Trammell, Proc. Intern. Atomic Energy Agency Symp. on Chemical Effects of Nuclear Transformations, Vol 1, p75, 1961