1. C.E. Barnes, U.S. Patent 2,309,727 (1943).
2. M.I. Shevchuk and A.V. Dombrowskii, Zh. Obshch. Khim. 34, 916 (1964); Chem. Abs. 15810 (1964).
3. J. Sam and J.R. Mozingo, J. Pharm. Sci. 58, 1030 (1969).
4. S. Watanabe et al., Yukagaku 25, 110 (1976); Chem. Abs. 84, 120611 (1976).
5. A. Gandini et al., in “Topics in Furan Chemistry”, J. Kovac, Ed.,Bratislava University Press, Bratislava, 1983, p.33.