1. A. N. Terenin, Photonics of Dye Molecules and Related Organic Compounds (Nauka, Leningrad, 1967) [in Russian].
2. I. M. Kogan, Chemistry of Dyes (Synthetic) (ONTI, Glavnaya Redaktsiya Khim. Literatury, Moscow, 1938) [in Russian].
3. P. F. Gordon and P. Gregory, Organic Chemistry in Colour (Springer, Berlin, 1983; Mir, Moscow, 1987).
4. A. T. Vartanyan, Izv. Akad. Nauk SSSR, Ser. Fiz. 20(4), 448 (1956).
5. A. T. Vartanyan, Zh. Fiz. Khim. 30(5), 1028 (1956).