1. M.I. Adamovich et al. EMU01-Collab.: Lund University Report LUIP 8706 (1987) to be published
2. M. El-Nadi et al. EMU03-Collab.: Cairo University preprint 1987
3. R. Holynski et al. KLM-Collab.: Louisiana State University Report HEA-88-87-04 (1987)
4. N. Ardito et al.: CERN Report CERN-EP/87-162 (1987)
5. P.L. Jain et al.: private communications