1. W. Heisenberg, Z. Phys. 77, 1 (1932)
2. I. Talmi,Simple models of complex nuclei: the shell model and the interacting boson model (Harwood, New York, 1993)
3. E.P. Wigner, Phys. Rev. 51, 106 (1937)
4. J.P. Elliott, Proc. Roy. Soc. (London) A245, 128 (1958)
5. J.P. Elliott, Proc. Roy. Soc. (London) A245, 562 (1958)