1. M. Chanon, Chem. Heterocycl. Compounds 34 (part II), 2.
2. B. Barone, M. Chanon, R. Gallo, Chem. Heterocycl. Compounds 34 (part II), 31.
3. G. Vernin, Chem. Heterocycl. Compounds 34 (part I), 232.
4. B. Barone, M. Chanon, R. Gallo, Chem. Heterocycl. Compounds 34 (part II), 52.