1. Beedle, R. E.: 1970, Preprint UNH-70-14, University of New Hampshire.
2. Bercovitch, M.: 1971a, Paper MOD-12, 12th Int. Conf. on Cosmic Rays, Hobart, 1971,Conference Papers (University of Tasmania)2, 579.
3. Bercovitch, M.: 1971b, Rapporteur Paper, 12th Int. Conf. on Cosmic Rays, Hobart, 1971,Conference Papers (University of Tasmania), in press.
4. Beuermann, K. P., Rice, C. J., Stone, E. C., and Vogt, R. E.: 1969,Phys. Rev. Letters 22, 412.
5. Burger, J. J.: 1971,Astrophys. J. 166, 651.