1. Erbudak, M., Eib, W.: Helv. Phys. Acta50, 147 (1977)
2. Keller, J.: Proc. III. Int. Conf. Computers in Chemical Research, Education and Technology, p. 225, Ludeña, E.V., Sabelli, N., Wahl, A.C. (eds.). New York (1977)
3. Eastman, D.E., Freeouf, J., Erbudak, M.: J. Physique C6, 37 (1973)
4. Keller, J.: J. Phys. C4, 3143 (1971) and J. Physique C3, 241 (1972)
5. Keller, J., Fritz, J., Garritz, A.: J. Physique C4, 379 (1974) and Keller, J.: AIP Conf. Proc.10, 514 (1973)