1. V. A. Ambartsumyan, Byull. Erevanskoi Astr. Obs., No. 6 (1945) [see also: Scientific Works, Vol. 1 [in Russian], Erevan (1960)].
2. B. Davison, Neutron Transport Theory, Oxford (1958).
3. V. V. Sobolev, Course of Theoretical Astrophysics [in Russian], Nauka, Moscow (1967).
4. V. V. Sobolev, in: Kinematics and Dynamics of Stellar Systems and Physics of the Interplanetary Medium [in Russian], Alma-Ata (1965).
5. D. I. Nagirner, Trudy AO LGU,22 (1965).