Approximate output regulation for a spherical inverted pendulum. - Leron Postelnik; Guangyu Liu 001; Karl A. Stol; Akshya Swain (ACC, 2011)

Approximate stable system centre approach to output tracking of non-minimum phase nonlinear systems. - Leron Postelnik; Akshya K. Swain; Karl A. Stol (J. Frankl. Inst., 2017)