The oxygen isotope effect on the infrared photo-induced absorption spectra of La2CuO4 R. V. Yusupov, K. Conder, T. Mertelj, D. Mihailovic, K. A. Müller and H. Keller Eur. Phys. J. B, 54 4 (2006) 465-469 Published online: 03 February 2007 DOI: 10.1140/epjb/e2007-00030-x