WASET
Nasir, A. , Ahmad, M. , Ismail, R.. "The Control of a Highly Nonlinear Two-wheels Balancing Robot: A Comparative Assessment between LQR and PID-PID Control Schemes". World Academy of Science, Engineering and Technology, Open Science Index 46, International Journal of Mechanical and Mechatronics Engineering, (2010), 4(10), 942 - 947.