1. M. Goeppert-Mayer, J.H.D. Jensen, Elementary Theory of Nuclear Shell Structure (Wiley, New York, 1955)
2. A. Bohr, B.R. Mottelson, Nuclear Structure Vol II: Nuclear Deformations (W.A. Benjamin, Inc., Reading, 1975)
3. A. Bohr, B.R. Mottelson, Nuclear Structure, vol. I (W.A.Benjamin Inc., Reading, 1969)
4. J.P. Elliott, Collective motion in the nuclear shell model I. Classification schemes for states of mixed configurations. Proc. Roy. Soc. (London) A245, 128–145 (1958)
5. J.P. Elliott, Collective motion in the nuclear shell model II. The introduction of intrinsic wave-functions. Proc. Roy. Soc. (London) A245, 562–581 (1958)