1. Thiersch, J.B., J. Reprod. Fert.4 (1962) 219.
2. Oettel, J., and Frohberg, H., Naunyn Schmiedebergs Arch. Pharmak.274 (1964) 363.
3. Tuchmann-Duplessis, M., and Mercier-Parot, L., C. r. Acad. Sci. Paris261 (1965) 241.
4. Roll, R., and Bär, F., Arzneimittel-Forsch.17 (1967) 610.
5. Kreybig, v. Th., Preussmann, R., and Schmidt, W., Arzneimittel-Forsch.18 (1968) 645.