LTR design of discrete-time proportional-integral observers. - Bahram Shafai; Stuart Beale; Hans Henrik Niemann; Jakob Stoustrup (IEEE Trans. Autom. Control., 1996)

Estimation and Rejection of Unknown Sinusoidal Disturbances Using a Generalized Adaptive Forced Balancing Method. - Elnaz Vahedforough; Bahram Shafai; Stuart Beale (ACC, 2007)