1. A. É. Aliev, V. V. Kuznetsov, L. A. Gaivoronskaya, and N. S. Prostakov, Khim. Geterotsikl. Soedin., No. 10, 1405–1408 (1989).
2. USSR Author's Certificate No. 366,844; Otkrytiya, No. 8, 7 (1973).
3. USSR Author's Certificate No. 425,607; ibid., No. 16, 13 (1974).
4. USSR Author's Certificate No. 736,583; ibid., No. 44 (1985).
5. R. S. Vartanyan, Khim.-farm Zh., No. 5, 540–550 (1983).