1. Optimum settings for automatic controllers;Ziegler;Trans. ASME,1942
2. Handbook of PI and PID Controller Tuning Rules;O’Dwyer,2003
3. Patents, software, and hardware for PID control: an overview and analysis of the current art;Li;IEEE Control Systems Magazine,2006
4. J. Nilsson, Real-time control systems with delays, Ph.D. Thesis, Lund Institute of Technology, Sweden, 1998.
5. B. Lincoln, Dynamic programming and time-varying delay systems, Ph.D. Thesis, Lund Institute of Technology, 2003.