[1] Pendry J B, Schurig D and Smith D R 2006 Science
312 1780

[2l] Leonhardt U 2006 Science 312 1777

[3] Greenleaf A, Lassas M and Uhlmann G 2003 Math. Res.
Lett. 10 685

[4] Cummer S A and Schurig D 2007 New J. Phys. 9
45

[5] Milton G W, Briane M and Willis J R 2006 New J.
Phys. 8 248

[6] Chen H Y and Chan C T 2007 Appl. Phys. Lett.
91 183518

[7] Cummer S A, Popa B I, Schurig D, Smith D R, Pendry J B,
Rahm M and Starr A 2008 Phys. Rev. Lett. 100 024301

[8] Norris A N 2008 URL http://arxiv.org/abs/0802.0701

[9] Norris A N 2008 URL http://arxiv.org/abs/0805.0080

[10] Chen H Y, Liang Z, Yao P, Jiang X, Ma H R and Chan C T
2007 Phys. Rev. B 76 241104(R)

[11] Schurig D, Mock J J, Justice B J, Cummer S A, Pendry J B,
Starr A F and Smith D R 2006 Science 314 977

[12] Cai W, Chettiar U K, Kildishev A V and Shalaev V M 2007
Nat. Photonics 1 224

[13] Cai W, Chettiar U K, Kildishev A V, Shalaev V M and
Milton G W 2007 Appl. Phys. Lett. 91 111105

[14] Yan M, Ruan Z and Qiu M 2007 Opt. Express 15
17772

[15] Cheng Y, Yang F, Xu J Y and Liu X J 2008 Appl. Phys.
Lett. 92 151913

[16] Schoenberg M and Sen P N 1983 J. Acoust. Soc. Am.
73 61

[17] Huang Y, Feng Y and Jiang T 2007 Opt. Express
18 11133

Wood B, Pendry J B and Tsai D P 2006 Phys. Rev. B
74 115116

[18] Cai L W and S\'{anchez-Dehesa J 2007 New J. Phys.
9 450