1. W. W. Duley and D. A. Williams, Interstellar Chemistry, 1984, Academic Press, London.
2. A. Dalgarno and J. H. Black, Rep. Prog. Phys. 39 (1976) 573
3. M. J. Howard and I. W. M. Smith, Prog. React. Kinet. 12 (1983) 55.
4. N. G. Adams, D. Smith, and D. C. Clary, Astrophys. J. 296 (1985) L31.
5. C. E. Dykstra Ed., Advanced Theories and Computational Approaches to the Electronic Structure of Molecules, Reidel, Dordrecht, 1984.