1. For a more detailed introduction see: W. Elenbaas et al. Fluorescent Lamps and Lighting, Philips Technical Library, 1959, Chapter IV.
2. F. M. Penning, Naturwiss. 15, 818, 1927; Zs. f. Phys.
46, 335, 1928.
3. H. Krefft & E. Summerer, Das Licht
4, 1, 1934;
4. H. Kreft, Zs. techn. Phys.
19, 345, 1938.
5. R. Küch and T. Retschinsky, Ann. Phys., Leipzig, 20, 563, 1906.