[1] Hawking S W 1974 Nature 30 248

[2] Hawking S W 1975 Commun. Math. Phys. 43 199

[3] Parikh M K and Wilczek F 2000 Phys. Rev. Lett. 85
5042

[4] Parikh M K 20 04 Int. J. Mod. Phys. D 13 2351

[5] Parikh M K 2004 hep-th/0402166

[6] Hemming S and Keski-Vakkuri E 2001 Phys. Rev. D 64
44006

[7] Medved A J M 2002 Phys. Rev. D 66 124009

[8] Setare M R and Vagenas E C 2005 Int. J. Mod Phys. A
20 7219

[9] Zhang J Y and Zhao Z 2005 Phys. Lett. B 618 14

[10] Yang S Z 2005 Chin. Phys. Lett. 22 2492

[11] Zhang J Y and Zhao Z 2005 J. High Energy Phys.
10 055

[12] Zhang J Y and Zhao Z 2006 Phys. Lett. B 638 110

[13] Ren J and Zhao Z 2006 Chin. Phys. 15 0292

[14] Ren J and Zhao Z 2006 Chin. Phys. Lett. 23
2019

[15] William A et al 1990 Phys. Rev. D 4 142

[16] Kraus P and Parentani R 2000 Nucl. Phys. B 575 333

[17] Yang S Z 2004 Acta Phys. Sin. 53 4007 (in Chinese)