E. G. Birgin, I. Chambouleyron and J. M. Martnez, “Es- timation of the Optical Constants and the Thickness of Thin Films Using Unconstrained Optimization,” Journal of Computational Physics, Vol. 151, No. 2, 1999, pp. 862-990. doi10.1006/jcph.1999.6224 - References - Scientific Research Publishing