1. Lopac, V.: Nucl. Phys. A138, 1 (1969)
2. Vanden Berghe, G., Degrieck, E.: Z. Physik262, 37 (1973)
3. Gill, R.D., Caraça, J.M.G., Cox, A.J., Rose, H.J.: Nucl. Phys. A187, 369 (1972)
4. Routti, J.T.: CERN report No 3414 (1970)
5. Lindhard, J., Scharff, M., Schiott, H.E.: Mat. Fys. Medd. Dan. Vid. Selks.33, No 14 (1963)