1. V. L. Ginzburg and L. D. Landau, Zh. Eksp. Teor. Fiz. 10, 1064 (1950).
2. P. G. de Gennes, Superconductivity of Metals and Alloys (Bengamin, New York, 1966).
3. M. Tinkham, Introduction to Superconductivity (Dover, New York, 2004).
4. G. J. Carty and D. P. Hampshire, Phys. Rev. B 77, 172501 (2008).
5. G. R. Berdiyorov, A. K. Elmurodov, and F. M. Peeters, Phys. Rev. B 79, 174506 (2009).