1. Waymouth, J.F., Electric discharge lamps, MIT Press ( 1971), p. 184.
2. Brown, S.C., Handbuch der Physik, vol. 22, Springer Verlag (1956), p. 531.
3. Nasser, E., Fundamentals of gaseous ionization and plasma electronics, Wiley (1971), p. 367.
4. De‐excitation cross sections of metastable argon by various atoms and molecules