1. Angel, J.R.P., Hill, J.M., Strittmatter, P.A., Salinari, R, Weigelt, G., Proc. SPIE Vol. 3350, p. 881–889 (1998)
2. Bahcall, J.N. and Tremaine, S.C., ApJ 244, 805 (1981)
3. Baganoff, F.K. et al., Proceedings of the Galactic Center Workshop, Nov. 3-8, 2002, Hawaii, A. Cotera, T. Geballe, S. Markoff, H. Falcke (editors), Astron. Nachrichten No. 324 in press (2003)
4. Baganoff, F.K., et al., Nature 413, 45 (2001)
5. Booth, A.J., et al., Proc. from ASP Conference Vol. 194. edited by Unwin, S., and Stachnik, R., p.256 (1999)