1. C. Reeves, thesis, University of Cambridge, England, 1957.
2. I. Cooper and R. McWeeny, J. Chem. Phys. 44, 226 (1966).JCPSA60021-9606
3. F. A. Matsen, Advan. Quantum Chem. 1, 59 (1964).AQCHA90065-3276
4. R. McWeeny and Y. Mizuno, Proc. Roy. Soc. (London) A259, 554 (1961).PRLAAZ1364-5021
5. R. McWeeny, J. Chem. Phys. 42, 1717 (1965).JCPSA60021-9606