[1] K. Bergmann, H. Theuer, and B. W. Shore, Rev. Mod. Phys. 70, 1003 (1998).
[2] I. R. Sola, V. S. Malinovsky, B. Y. Chang, J. Santamaria, and K. Bergmann, Phys. Rev. A 59, 4494 (1999).
[3] R. G. Unanyan, L. P. Yatsenko, K. Bergmann, and B. W. Shore, Opt. Commun. 139, 48 (1997).
[4] J. Cheng and J. Zhou, Phys. Rev. A 64, 065402 (2001).
[5] M. Fleischhauer, R. Unanyan, B. W. Shore, and K. Bergmann, Phys. Rev. A 59, 3751 (1999).
[6] R. W. Ziolkowski, J. M. Arnold, and D. M. Gogny, Phys. Rev. A 52, 3082 (1995).
[7] M. Muller, V. P. Kalosha, and J. Herrmann, Phys. Rev. A 58, 1372 (1998).
[8] S. Hughes, Phys. Rev. Lett. 81, 3363 (1998).
[9] X. Song, S. Gong, S. Jin, and Z. Xu, Phys. Rev. A 69, 015801 (2004).
[10] C. Liu, S. Gong, Z. Zheng, and Z. Xu, Chin. Opt. Lett. 1, 423 (2003).
[11] http://physics.nist.gov/PhysRefData/handbook/element_name.htm.
[12] N. V. Vitanov, M. Fleischhauer, B. W. Shore, and K. Bergmann, Advances Atomic, Molecular, and Optical Physics 46, 55 (2001).
[13] S. Jin, S. Gong, R. Li, and Z. Xu, Phys. Rev. A 69, 023408 (2004).
[14] J. Cao, C. J. Bardeen, and K. R. Wilson, Phys. Rev. Lett. 80, 1406 (1998).