1. ?orm, F., Nov�k, J., Herout, V.: Chem. listy47, 1097 (1953).
2. Heubner, W., Albath, W.: Arch. exp. Pathol. Pharmacol.192, 383 (1939).
3. Ko?ov�, V.: Acta Fac. pharm. Brun. Bratisl.2, 72 (1959).
4. Stahl, E.: Pharmazie (Berlin)7, 863 (1952).
5. Tyih�k, E., et al.:ibid.18, 566 (1963).