1. H. Eyring, J. Walter, G.E. Kimball, Quantum Chemistry, John Wiley and Sons, New York 1944.
2. T. Veszprémi and M. Fehér, Quantum Chemistry: Fundamentals to applications, Kluwer Academic/Plenum New York, 1999.
3. G. A. Korn and T. M. Korn, Mathematical Handbook. for Scientists and Engineers, MacGrawHill, New York 1961.
4. E. Szondy and T. Szondy, Acta Phys. Hung. 20, 253 (1966)
5. S. F. Boys, Proc. Roy. Soc. A309, 195 (1969)