Investigation of highly excited states of calcium by three-photon ionizationR. S. Dygdała, A. Zawadzka, D. Lisak, P. Płóciennik and R. S. TrawińskiEur. Phys. J. D, 30 1 (2004) 15-22DOI: https://doi.org/10.1140/epjd/e2004-00071-9