C.-R. Hu, Phys. Rev. Lett. 72, 1526 (1994).
Y. Tanaka and S. Kashiwaya, Phys. Rev. Lett. 74, 3451 (1995); Phys. Rev. B 53, 11957 (1996).
Yu. S. Barash, A. A. Svidzinsky, and H. Burkhardt, Phys. Rev. B 55, 15282 (1997).
M. Fogelström, D. Rainer, and J. A. Sauls, Phys. Rev. Lett. 79, 281 (1997).
Yu. N. Ovchinnikov, Zh. Éksp. Teor. Fiz. 56, 1590 (1969) [Sov. Phys. JETP 29, 853 (1969)].
F. J. Culetto, G. Kieselmann, and D. Rainer, in Proceedings of the 17th International Conference on Low Temperature Physics, edited by U. Eckern, A. Schmid, W. Weber, and H. Wuhl, North Holland, Amsterdam, 1984, p. 1027.
A. A. Golubov and M. Yu. Kupriyanov, JETP Lett. 67, 501 (1998).
N. B. Kopnin, P. I. Soininen, and M. M. Salomaa, Low Temp. Phys. 85, 267 (1991).
G. Eilenberger, Z. Phys. 214, 195 (1968).
N. Schopohl and K. Maki, Phys. Rev. B 52, 490 (1995); N. Schopohl, http://xxx.lanl.gov/abs/cond-mat/9804064.
E. Schachinger, J. P. Carbotte, F. Marsiglio, Phys. Rev. B m 56, 2738 (1997).
A. V. Zaitsev, Zh. Éksp. Teor. Fiz. 86, 1742 (1984) [Sov. Phys. JETP 59, 1015 (1984)].
Yu. S. Barash, H. Burkhardt, and D. Rainer, Phys. Rev. Lett. 77, 4070 (1996).
Y. Tanaka and S. Kashiwaya, Phys. Rev. B 56, 892 (1997).
M. P. Samanta and S. Datta, Phys. Rev. B 55, R8689 (1997).
R. A. Riedel and P. F. Bagwell, Phys. Rev. B 57, 6084 (1998).