1 M.. Sikora, H.. Sol, M.C. Begelman, and G.M. Madejski, Astronomy and Astrophysics Supplement 120, (1996).
1 B.E. Stern, J.. Poutanen, R.. Svensson, M.. Sikora, and M.C. Begelman, The Astrophysical Journal 449, (1995).
1 M.C. Begelman, and M.J. Rees, Gravity "Fatal Attraction": Black Holes in the Universe, First (Cambridge University Press, 1995).
1 B.E. Stern, M.C. Begelman, M.. Sikora, and R.. Svensson, Monthly Notices of the Royal Astronomical Society 272, (1995).
1 G.M. Madejski, C.. Done, T.J. Turner, R.F. Mushotzky, P.. Serlemitsos, F.. Fiore, M.. Sikora, and M.C. Begelman, in Unknown (AIP, College Park, Maryland (USA), 1994).