1. H. Harari: Phys. Rev. Lett.22, 562 (1969)
2. J.L. Rosner: Phys. Rev. Lett.22, 689 (1969)
3. See some earlier general reviews, G.F. Chew, Proc. of 3rd European Symposium onN $$\bar N$$ interactions, Stockholm (1976)
4. M. Fukugita, K. Igi Phys. Rep.31C, 237 (1977)
5. L. Montanet: Proc. of ?XIV Rencontre de Moriond?, ed. J. Tran Thanh Van, 1979. Also different talks in the ?Workshop on baryonium and other unusual hadron states? IPN Orsay, June 1979