1. Serot, B.D., Walecka, J.D.: Adv. Nucl. Phys., vol. 16, Negele, J.W., Vogt, E. (eds.). New York: Plenum Press 1985
2. Reinhard, P.-G.: Rep. Prog. Phys.52, 439 (1989)
3. Theis, J., Graebner, G., Buchwald, G., Maruhn, J., Greiner, W., St�cker, H., Polonyi, J.: Phys. Rev. D28, 2286 (1983)
4. Shor, A. et al.: Phys. Rev. Lett.62, 1829 (1989); ibid.63, 2192 (1989)
5. Costales, J., E802 collaboration: Talk presented at the Workshop on Heavy Ion Physics at AGS (BNL, Upton, March 1990)