1. V. A. Ambartsumian, Proc. 11th Solvay Conf. Physics, R. Stoops, ed., Brussels (1958), p. 241.
2. V. A. Ambartsumian, Astron. J. 66, 536 (1961).
3. D. B. Sanders and I. F. Mirabel, Ann. Rev. Astron. Astrophys. 34, 749 (1996).
4. IRAS, Joint IRAS Science W. G., IRAS Catalog of Point Sources, Version 2.0 (1986).
5. M. Moshir, G. Kopan, T. Conrow, et al., IRAS Faint Source Catalog, v. 2.0, NASA (1990).