The improved IMC disturbance rejection procedure was suggested by Braatz and co-workers: Horn, I. G., J. A. Arulandu, C. J. Gombas, J. G. VanAntwerp, and R. D. Braatz , “Improved Filter Design in Internal Model Control,” Ind. Eng. Chem. Res., 35(10), 3437–3441 (1996).
A complete IMC design procedure is presented in the following: Morari, M., and E. Zafiriou , Robust Process Control, Prentice-Hall, Upper Saddle River, NJ (1989).