1 J.M. Shull, J.. Tumlinson, M.L. Giroux, G.A. Kriss, and D.. Reimers, The Astrophysical Journal 600, (2004).
1 K.M. McLin, J.T. Stocke, R.J. Weymann, S.V. Penton, and J.M. Shull, The Astrophysical Journal 574, (2002).