Dufour P, Jandl S, Banville M, Fournier P, Aubin M. Infrared reflectance of YBa2(Cu1-xFex)3O7-u. Physica C: Superconductivity and its applications. 1990;166:431-6.
Jandl S, Banville M, Pepin C. Far-infrared study of Y2BaCuO5-x. Solid State Communications. 1988;67:417-20.