1. Wei, P.H.L., US Patent no. 4 327 221, 1982.
2. Claremon, D.A., Friedman, P.A., Remy, D.C., and Stern, A.M., US Patent no. 4 968 494, 1990.
3. Kim, D.G., Sudolova, N.M., and Slepukhin, P.A., Chem. Heterocycl. Compd., 2011, vol. 47, no. 5, p.631.
4. Tarasova, N.M. and Kim, D.G., Vestn. Yuzhno-Ural. Gos. Univ., Ser. Khim., 2015, vol. 7, no. 2, p.4.
5. Tarasova, N.M., Kim, D.G., and Slepukhin, P.A., Chem. Heterocycl. Compd., 2015, vol. 51, no. 10, p.923.