1. M. J. Rees, Nature (London, U.K.) 211, 468 (1966).
2. G. Rybicki and A. Lightman, Radiative Processes in Astrophysics (New York: Wiley, 1979).
3. J. Terrell, Phys. Rev. 116, 1041 (1960).
4. K. R. Lind and R. D. Blandford, Astrophys. J. 295, 358 (1985).
5. A. P. Marscher, in The Jet Paradigm from Microquasars to Quasars, Ed. by T. Belloni (Springer, Berlin, Heidelberg, 2010), p. 173.