Integrator Backstepping using Barrier Functions for Systems with Multiple State Constraints. - Khoi B. Ngo; Robert E. Mahony; Zhong-Ping Jiang (CDC/ECC, 2005)

Bounded Torque Control for Robot Manipulators Subject to Joint Velocity Constraints. - Khoi B. Ngo; Robert E. Mahony (ICRA, 2006)