1. J. Elguero, C. Marcin, A. R. Katrizky, P. Linda, Adv. Heterocycl. Chem., 1976, Suppl. 1, (a) 336; (b) 313.
2. L. A. Fedorov, Spektroskopiya YaMR organicheskikh analiticheskikh reagentov i ikh kompleksov s ionami metallov [NMR Spectroscopy of Organic Analytical Reagents and Their Complexes with Metal Ions], Nauka, Moscow, 1987, 80 (in Russian).
3. R. M. Christie, Colour Chemistry, Royal Society of Chemistry, Cambridge, 2001, 50.
4. A. D. Garnovskii, I. S. Vasil’chenko, Usp. Khim., 2005, 74, 211 [Russ. Chem. Rev., 2005, 74, 193 (Engl. Transl.)].
5. V. I. Minkin, A. D. Garnovskii, J. Elguero, A. R. Katritzky, O. V. Denisko, Adv. Heterocycl. Chem., 2000, 76, 157.