Investigation of highly excited states of calcium by three-photon ionization R. S. Dygdała, A. Zawadzka, D. Lisak, P. Płóciennik and R. S. Trawiński Eur. Phys. J. D, 30 1 (2004) 15-22 Published online: 18 May 2004 DOI: 10.1140/epjd/e2004-00071-9