1. H. Wiehe (editor), Advances in the Chemistry of Acetylenic Compounds [Russian translation], Khimiya, Moscow (1973), p. 247.
2. B. Ya. Karele, L. É. Treigute, S. V. Kalnin', I. P. Grinberga, and O. Ya. Neiland, Khim. Geterotsikl. Soedin., No. 2, 214 (1974).
3. L. G. Yudin, V. A. Budylin, A. N. Kost, and V. I. Minkin, Dokl. Akad. Nauk SSSR, 176, 1096 (1967).
4. J. C. Powers, J. Org. Chem., 31, 2627 (1966).
5. R. Weissberger, Ber., 46, 651 (1913).