1. D. M. Antonov, L. I. Belen'kii, V. S. Bogdanov, A. A. Dudinov, M. M. Krayushkin, V. N. Nesterov, Yu. T. Struchkov, and B. I. Ugrak, Khim. Geterotsikl. Soedin., No. 11, 1451 (1992).
2. A. A. Dudinov, D. M. Antonov, L. I. Belen'kii, and M. M. Krayushkin, Carbonyl Compounds in the Synthesis of Heterocycles [in Russian], Part 1, Saratov (1989), p. 4.
3. Y. Sasson and G. Rempel, Synthesis, 5, 449 (1975).
4. D. M. Antonov, L. I. Belen'kii, V. S. Bogdanov, A. A. Dudinov, B. I. Ugrak, and M. M. Krayushkin, ?The chemistry and technology of furan compounds. Synthesis, stereochemistry and properties of furan derivatives,? in: Interuniversity Collection of Scientific Transactions [in Russian], Krasnodar (1990), p. 21.
5. N. R. Smyrl and R. W. Smithwick, J. Heterocycl. Chem., 19, 493 (1982).