1. R. L. Kelly, unpublished level list prepared for line classifications published in J. Phys. Chem. Ref. Data, 16, Suppl, 1, 1987
2. Atomic Transition Probabilities (Na through Ca);Wiese,1969
3. J. R. Fuhr, and, W. L. Wiese, CRC Handbook of Chemistry and Physics, edited by, D. R. Lide, Vol, 78, CRC Press Inc, 1998
4. W. Hofmann, Z. Naturforsch. Teil A, 22, 2097, 1967, (German)
5. G. M. Lawrence, Astrophys. J, 148, 261, 1967