1. V. A. Ambartsumian, Stars, Nebulae, and Galaxies [in Russian] Izd-vo. Arm. SSR (1969), p. 283.
2. V. A. Ambartsumian, L. V. Mirzoyan, É. S. Parsamian, et al., Astrofizika 6, 7 (1970).
3. V. A. Ambartsumian, Astrofizika 6, 31 (1970).
4. V. A. Ambartsumian, L. V. Mirzoyan, É. S. Parsamian et al., Astrofizika 7, 319 (1971).
5. V. A. Ambartsumian and L. V. Mirzoyan, IAU Colloquium No. 15, Bamberg (1971), p. 98.