1. Arcimowicz, B.: 7th E.G.A.S. Conference, Kracow (1975)
2. Voss, M., Weiss, W., Winkler, R.: 15th E.G.A.S. Conference, Madrid (1983)
3. Howard, L.E., Andrew, K.L.: Symposium for atomic spectroscopy, Berkeley (1983)
4. Bouazza, S., Abjean R., Guern, Y.: 14th E.G.A.S. Conference, Liège (1982)
5. Moore, C.E.: Atomic energy levels, circ 467, Nat. Bur. Standard (1952)