1. Catchpole, R., Boksenberg A., et al. 1996, in Science with the Hubble Space Telescope-II, ed. P. Benvenuti, F.D. Macchetto & E.J. Schreier (Space Telescope Science Institute), 219.
2. Evans, D.W. 2001, in ASP Conf. Sere 232, The New Era of Wide Field Astronomy, ed. R.G. Clowes, A.J. Adamson & G.E. Bromage (San Francisco: ASP), 329.
3. Fukugita, M., Ichikawa, T., Gunn, J.E., Doi, M., Shimasaku, K., & Schneider, D.P. 1996, AJ, 111, 1748.
4. Helmer, L., & Morrison, L.V. 1985, Vistas Astron., 28,505.
5. Hilton, J., & Stone, R.C. 1998, in IAU Coll. 172, Impact of Modern Dynamics in Astronomy, ed. J. Henrard & S. Ferraz-Mello (Dordrecht: Kluwer), 361.