1. Serot, B.D., Walecka, J.D.: In: Advances in nuclear physics. Negele, J.W., Vogt, E. (eds.), Vol. 16. New York: Plenum Press 1985
2. Bernard, V. et al.: Nucl. Phys. A412, 349 (1984)
3. Witten, E.: Nucl. Phys. B160, 57 (1979)
4. Lenz, F., Thies, M., Levit, S., Yazaki, K.: Preprint Erlangen 1990. Ann. Phys. (submitted for puplication)
5. Zahed, I.: Phys. Rev. C37, 409 (1988)