1. Blake, J.B. and Schramm, D.N. 1974, Ap. Space Sci. 30, 275.
2. Burnett, T.H. et al. 1990 Ap. J. (Letters) , 349 L25, and 21st Internat. Cosmic Ray Conf. (Adelaide) 3, 101.
3. Cameron, A.G.W. 1982, in “Essays of Nuclear Astrophysics,” ed. C. Barnes, R.N. Clayton and D.N. Schramm, Cambridge Univ. Press, p.23.
4. Casse, M., Goret, P., and Cesarsky, C.J.: 1975, 14th Intl. Cosmic-Ray Conf. (Munich) 2, 646.
5. Eichler, D. and Hainebach, K. 1981, Phys. Rev. Letter, 47, 1560.