1. D. Bates and A. Damgaard, Phys. Trans., A242:101 (1949).
2. I. B. Levinson and A.A. Nikitin, Handbook on the Theoretical Computation of Line Intensities in Atomic Spectra [in Russian], Izd-nie LGU, Leningrad, 1962.
3. C. W. Allen, Astrophysical Quantities, Oxford Univ. Press, 1960.
4. A. V. Vasil’ev, G. G. Dolgov-Savel’ev, and V. I. Kogan, Nucl. Fusion, Suppl., Part 2, p. 655 (1962).
5. G. Knorr, Z. Naturforsch., 13a:941 (1958).