Zahiripour, S. A., Jalali, A. A.. “Designing an Optimal Proportional-Integral Sliding Surface for a Quarter Car Active Suspension System with Suspension Components Possessing Uncertain Constants and Nonlinear Characteristics.” Nashriyyah -i Muhandisi -i Barq va Muhandisi -i Kampyutar -i Iran, vol. 10, no. 3, 2012, pp. 113-118.