1. P. Laurent et al. in Laser Spectroscopy XIV R. Blatt J. Eschner D. Leibfried F. Schmidt-Kaler Eds. (World Scientific Singapore 1999) pp. 41–50.
2. S. R. Jefferts D. M. Meekhof J. H. Shirley M. Stepanovic T. E. Parker in Proceedings of the 2000 IEEE International Frequency Control Symposium Kansas City 7 to 9 June 2000 (IEEE Piscataway NJ 2000) pp. 714–717.
3. S. Weyers R. Schröder A. Bauch in Proceedings of the 15th European Frequency and Time Forum Neuchâtel Switzerland 6 to 8 March 2001 (Fondation Suisse pour la Recherche en Microtechnique Neuchâtel Switzerland in press).
4. S. Weyers U. Hübner R. Schröder Chr. Tamm
5. Bauch A., Metrologia 38, 4 (2001).