1. L. D. Landau and E. M. Lifshitz, Course of Theoretical Physics, Vol. 9: E. M. Lifshitz and L. P. Pitaevskii, Statistical Physics: Part 2 (Nauka, Moscow, 1978; Butterworth-Heinemann, Oxford, 1980).
2. E. P. Gross, Nuovo Cimento 20, 454 (1961).
3. L. P. Pitaevskiĭ, Zh. Éksp. Teor. Fiz. 40, 646 (1961) [Sov. Phys. JETP 13 451 (1961)].
4. L. P. Pitaevskii, Usp. Fiz. Nauk 168(6), 641 (1998) [Phys.—Usp. 41 (6), 569 (1998)].
5. L. P. Pitaevskii, Usp. Fiz. Nauk 178(4), 346 (2006) [Phys.—Usp. 49 (4), 333 (2006)].