1. U. Griebner, V. Petrov, K. Petermann, and V. Peters, Opt. Express 12, 3125 (2004)
2. J. Kong, D. Y. Tang, J. Lu, K. Ueda, H. Yagi, and T. Yanagitani, Opt. Lett. 29, 1212 (2004).
3. M. Fechner, A. Kahn, H. Scheife, K. Petermann, and G. Huber, in CLEO/Europe-IQEC 2007, June 2007, Technical Digest.
4. N. Ter-Gabrielyan, L. D. Merkle, G. A. Newburgh, M. Dubinskii, and A. Ikesue, in Proc. of the Advanced Solid-State Photonics Conf. 2008, TuB4, Jan. 29, 2008.
5. N. Ter-Gabrielyan, L. D. Merkle, A. Ikesue, and M. Dubinskii, Opt. Lett. 33, 1524 (2008).