[1] Fleischmann M, Hendra P J, McQuillan A J. Chem. Phys. Lett., 1974, 26: 163.
[2] Jeanmaire D J, Van Duyne R P. J. Electroanal. Chem., 1977, 84: 1.
[3] Tian Z Q. J. Raman Spectrosc., 2005, 36: 466.
[7] Miguel A G, Rosa P, Maquieira A. Trends in Analytical Chemistry, 1999, 18: 204.
[8] Frens G. Nature Phy. Sci., 1973, 241: 20.