1. E. Clementi, in Proceedings of the Robert A. Welch Foundation Conferences on Chemical Research, Theoretical Chemistry, vol. 16 (Welch Foundation, Houston, 1973), p. 117
2. R.G. Parr, in Proceedings of the NATO Advanced Study Institute on density functional methods in physics (Alcabideche, Portugal, 1983)
3. P.W. Anderson, Rev. Mod. Phys. 50, 191 (1978). DOI 10.1103/RevModPhys.50.191
4. P.W. Anderson, Phys. Rev. 124, 41 (1961). DOI 10.1103/PhysRev.124.41
5. N.H. March, Adv. Phys. 6(21), 1 (1957). DOI 10.1080/00018735700101156