1. K. Abazajian, J. K. Adelman-McCarthy, M. A. Agueros, et al. (SDSS Collab.), Astron. J. 128, 502 (2004).
2. V. L. Afanasiev, S. N. Dodonov, A. V. Moiseev, et al., Preprint No. 139, SPb Filial SAO RAN (St. Petersburg Branch of Spec. Astrophys. Obs., Russ. Acad. of Sci., 2002).
3. V. L. Afanasiev, S. N. Dodonov, A. V. Moiseev, et al., Astron. Zh. 80, 409 (2003) [Astron. Rep. 47, 377 (2003)].
4. W. A. Baum, Proc. IAU Symp. 15, Problems of Extra-Galactic Research, Ed. by G. C. McVittie (Macmillan Press, New York, 1962), p. 390.
5. S. A. Baum, E. L. Zirbel, and C. P. O’Dea, Astrophys. J. 451, 88 (1995).