1. J.C. Stevens, F.J. Timmers, D.R. Wilson, G.F. Schmidt, P.N. Nickias, R.K. Rosen, G.W. Knight, S. Lai, European Patent Appl. 416815, priority 31/8/89 to Dow Chemicals.
2. J.M. Cannich European Patent Appl. 420436 to Exxon Chemical, priority 13/9/89.