“Infrared magneto-optical studies of La0.67Ca 0.33MnO3 single crystals: Magnetoconductivity at optical frequencies”, A. V. Boris, N. N. Kovaleva, A. V. Bazhenov, P. J. M. van Bentum, Th. Raising, S-W. Cheong, A. V. Samoilov, and N.-C. Yeh, Phys. Rev. B59, Rapid Communications, R697 (1999).
http://journals.aps.org/prb/abstract/10.1103/PhysRevB.59.R697