1. Univerza E. Kardelja v Ljubljani and Lek - Ljubljana, Yugoslav Patent Application 2092/90 (1990).
2. Laboratoire Roger Bellon, French Demande, 2,024,816 (1970);
3. Chem. Abstr., 75, 20414q (1970).
4. Roussel-Uclaf, French Demande 2,565,976 (1985);