1. EP Patent No. 97023. Chem Abstr.,100, No. 174519z (1984).
2. EP Patent No. 98141, ibid.,101, No. 72514x (1984).
3. EP Patent No. 99672, ibid.,101, No. 38262d (1984).
4. EP Patent No. 99673, ibid.,101, No. 54790e (1984).
5. EP Patent No. 104631, ibid.,101, No. 151671 (1984).