1. Abraham, R.G., et al. 1996, MNRAS 279, L47
2. Alladin, S.M. 1965, ApJ 141, 768
3. Amram, P., Marcelin, M., Boulesteix, J., & le Coarer, E. 1992, A&A 266, 106
4. Appleton, P.N., & Struck-Marcell, C. 1987, ApJ 312, 566
5. Appleton, P.N., & Struck-Marcell, C. 1996, Fundamentals Cosmic Phys. 16, 111