K. Havre and S. Skogestad, ``Effect of RHP zeros and poles on performance in multivariable systems,'' UKACC Conference Control'96, Exeter, UK, Sept. 1996, 930-935.

Abstract.
This paper examines the implications of RHP-zeros and poles on performance of multivariable feedback systems. The results quantify the fundamental limitations imposed by RHP-zeros and poles in terms of lower bounds on the peak of the weighted sensitivity and complementary sensitivity functions.