1. H. van der Plas, Ring Transformations of Heterocycles, Academic Press, London, New York (1973), vol. 1, 2.
2. O. P. Shvaika and V. N. Artemov, Usp. Khim., 41, 1788 (1972).
3. A. T. Balaban, A. Dinculescu, G. N. Dorofeenko, G. W. Fischer, A. V. Koblic, and V. V. Mezheritskii, W. Schroth, in: A. R. Katritzky (editor), Advances in Heterocyclic Chemistry, Suppl. 2, Academic Press, New York (1982).
4. H. Ohno, Electrochemical Aspects of Ionic Liquids, John Wiley & Sons, Inc., New Jersey (2005).
5. D. Bourissou, O. Guerret, F. P. Gabbai, and G. Bertrand, Chem. Rev., 100, 39 (2000).