1. Hertel, I.V., Stoll, W.: Adv. At. Mol. Phys.13, 113 (1978)
2. Pascale, J., Olson, R.E.: J. Chem. Phys.64, 3538 (1976)
3. Pascale, J., Perrin, M.Y.: J. Phys. B13, 1839 (1980)
4. Cuvellier, J., Berlande, J., Benoit, C., Mestdagh, J.M., de Mesmay, J.: J. Phys. B12, L461 (1979)
5. Baylis, W.E.: Private communication (1973)