Optical study of an untwinned (Bi1.57Pb0.43)Sr2CaCu2O8+8 single crystal: ab-plane anisotropy H. L. Liu, M. A. Quijada, D. B. Tanner, H. Berger and G. Margaritondo Eur. Phys. J. B, 8 1 (1999) 47-56 Published online: 15 March 1999 DOI: 10.1007/s100510050667