1. Yu. E. Lozovik and V. I. Yudson, Pis’ma Zh. Éksp. Teor. Fiz. 22, 556 (1975) [JETP Lett. 22, 274 (1975)]; Zh. Éksp. Teor. Fiz. 71, 738 (1976) [Sov. Phys. JETP 44, 389 (1976)]; Solid State Commun. 19, 391 (1976); Solid State Commun. 21, 211 (1977); Yu. E. Lozovik and V. N. Nishanov, Fiz. Tverd. Tela (Leningrad) 18, 3267 (1976) [Sov. Phys. Solid State 18, 1905 (1976)]; Yu. E. Lozovik and A. M. Ruvinskiĭ, Zh. Éksp. Teor. Fiz. 112, 1791 (1997) [JETP 85, 979 (1997)]; Yu. E. Lozovik, in Proceedings of Conference on Dielectric Electronics (FAN, Tashkent, 1973), p. 63.
2. A. Filinov, P. Ludwig, Yu. E. Lozovik, et al., J. Phys: Conf. Ser. 35, 197 (2006).
3. S. A. Moskalenko and D. W. Snoke, Bose-Einstein Condensation of Excitons and Biexcitons and Coherent Nonlinear Optics with Excitons (Cambridge Univ. Press, Cambridge, 2000).
4. D. Snoke, Science 298, 1368 (2002); R. Rapaport and G. Chen, J. Phys.: Condens. Matter 19, 295207 (2007); Z. Vörös, V. Hartwell, D. W. Snoke et al., J. Phys.: Condens. Matter 19, 295216 (2007).
5. V. B. Timofeev, Usp. Fiz. Nauk 175, 315 (2005) [Phys. Usp. 48, 295 (2005)].