I would consider the following reference as the most important:

A. Bemporad, M. Morari, V. Dua, E. Pistikopoulos, "The explicit solution of model predictive control via multiparametric quadratic programming", Proceedings of the American Control Conference, Chicago, Illinois, pp.872-876, 2000.

(available at http://www.aut.ee.ethz.ch/~bemporad)