1. March, J., “Advanced Organic Chemistry: Reactions, Mechanisms and Structure,” McGraw-Hill, New York, N.Y., 1968, p. 587.
2. Topchiev, A.V., S.V. Zavgorodnii, and Ya. M. Paushkin, in “Boron Trifluoride and Its Compounds as Catalysts in Organic Chemistry,” Vol. 2, Edited by W. Doering and D.H.R. Barton, Pergamon Press, New York, N.Y., 1959, p. 223.
3. Ely, L.T. (Standard Oil Development Co.), U.S. Patent 2,382,700 (1945).
4. Bell, R.T., and C.M. Thacker (Pure Oil Co.), U.S. Patent 2,447,481 (1948).
5. Greensfelder, B.S., and R.J. Moore (Shell Development Co.), Brit. Patent 603,103 (1948).