1. K. Sandros, Acta Chem. Scand.,18, No. 10, 2355?2374 (1964).
2. K. Kikuchi, H. Kokubuu, and M. Koizumi, Bull. Chem. Soc. Jpn.,43, No. 9, 2732?2739 (1970).
3. G. A. Ketsle, L. V. Levshin, and Yu. A. Soinikov, Izv. Akad. Nauk SSSR, Ser. Fiz.,39, No. 9, 1840?1844 (1975).
4. S. Parker, Photoluminescence of Solutions [Russian translation], Moscow (1972).
5. J. B. Birks, Photophysics of Aromatic Molecules (1970).