1. S. B. Seredenin, Yu. A. Blednov, V. L. Savel?ev, et al., RF Pat. No. 2,061,686; Byull. Izobret., No. 16 (1996).
2. A. N. Lomakin, A. M. Simonov, and V. A. Chigirina, Zh. Obshch. Khim., 33(2), 204 – 207 (1964).
3. A. M. Berkengeim, Chemistry and Technology of Synthetic Drugs [in Russian], ONTI, Glavnaya Redaktsiya Khimicheskoi Literatury, Moscow (1935), p. 439.
4. A. M. Simonov and P. A. Uglov, Zh. Obshch. Khim., 21(5), 884 – 888 (1951).
5. L. Weinberger and A. R. Day, J. Org. Chem., 24(10), 1451 – 1455 (1959).