1. P.‐O. Löwdin, Phys. Rev. 97, 1509 (1955).PHRVAO0031-899X
2. R. Pauncz, J. de Heer, and P.‐O. Löwdin, J. Chem. Phys. 36, 2247 (1962).JCPSA60021-9606
3. R. Pauncz, J. de Heer, and P.‐O. Löwdin, J. Chem. Phys. 36, 2257 (1962).JCPSA60021-9606
4. J. de Heer, J. Chem. Phys. 37, 2080 (1962).JCPSA60021-9606
5. J. de Heer, J. Phys. Chem. 66, 2288 (1962).JPCHAX0022-3654