1. D. A. Rowlands and J. B. Taylor, German Patent 2,722,772 (1977);
2. Chem. Abstr., 88, 89679r (1978).
3. P. J. Ramm and A. C. Barnes, Belgium Patent 878028 (1980);
4. Chem. Abstr., 94, 47354z (1981).
5. S. B. Kadin and P. F. Moore, U. S. Patent 4,031,217 (1977);