1. German Offenlegungsschrift 2,323,543 (1975), Montecatini Edison Corp.
2. Chem. Abstr., 80, 61068 (1974).
3. a German Offenlegungsschrift 2,627,867 (1977); Montecatini Edison Corp.
4. Chem. Abstr., 86, 91746n (1977).
5. b European Patent Application 50872 (1982).