R.  Uzdin, Segev, M. , and Salamo, G.J. . 2001. ?Theory Of Self-Focusing In Photorefractive Inp.?. Optics Letters, 26, Pp. 1547. http://search.ebscohost.com/login.aspx?direct=true&db=edselc&AN=edselc.2-52.0-0000384782&site=eds-live.