1. Chiang, J. & Dermer, C. D. 1997, ApJL, submitted (astro-ph/9708035)
2. Connaughton, V., etal 1998, in preparation
3. Dar, A. 1997a, in Very High Energy Phenomena in the Universe, ed. Y. Giraud-Heraud & J. Tran Thanh Van (Gif-sur-Yvette: Editions Frontieres), 69
4. Dar, A. 1997b, Phys. Rev. Lett., submitted (astro-ph/9708042)