1. (1) J.F. Waymouth, F. Koury, W.C. Gungle and C. Peterson: Illum. Engng, 62, (1967) 214
2. (2) J.F. Waymouth: Electric Discharge Lamps, p. 257, The M. I. T. Press, (1971)
3. (3) J.F. Waymouth, W.C. Gungle, J.M. Harris and F. Koury: Illum. Engng, 60, (1965) 85
4. Starting Phenomena of Metal Halide Lamps containing Iodides of Sc, Th and Na
5. (5) A.C G. Mitchell and M.W. Zemansky: Resonance Radiation and Excited Atoms, p. 79, The Cambrigde University Press, (1961)