1. C.V. McDaniel, P.K. Maher: Soc. Chem. Ind. (London), p. 186 (1968).
2. P.K. Maher, C.V. McDaniel: U.S. Patent, 3 293 192 (1966).
3. P.K. Maher, C.V. McDaniel: U.S. Patent, 3 402 996 (1968).
4. C.V. McDaniel, P.K. Maher: U.S. Patent, 3 449 070 (1969).
5. G.T. Kerr: J. Phys. Chem., 73, 2780 (1969).