1. A. Ingendoh, F. Berschauer, B. Backer, W. Stendel, B. Homeyer, M. Scheer, A. Jong, G. Hanssler, and P. Reinecke, German Unexamined Patent 3,418,395 GB. Ref. Zh., Khim., Abstract No. 20O349 (1986).
2. H. Berenson, USA Patent 3,931,406. Chem. Abstr., 84, Abstract No. 105587 (1976).
3. H. Ohyama, S. Takada, K. Morita, and S. Yamamura, German Unexamined Patent DE 3,246,847. Chem. Abstr., 99, Abstract No. 194945 (1983).
4. C. H. Boehringer, French Patent 1,560,344. Chem. Abstr., 72, Abstract No. 79018e (1970).
5. N. M. Omar, R. I. Mrongovius, and K. E. Schulte, Eur. J. Med. Chem., Chim. Ther., 14, 23 (1979).