1. Åström, K. J., & Hägglund, T. (2006). Advanced PID Control. Charlotte: Instrument Society America.
2. Atherton, D. P. (1975). Nonlinear Control Engineering—Describing Function Analysis and Design. Workingham: Van Nostrand.
3. Bartolini, G., Pisano, A., Punta, E., & Usai, E. (2003). A survey of applications of second order sliding mode control to mechanical systems. International Journal of Control, 76(9/10), 875–892.
4. Bartolini, G., Ferrara, A., & Usai, E. (1997). Output tracking control of uncertain nonlinear second-order systems. Automatica, 33(12), 2203–2212.
5. Boiko, I. (2005). Method and apparatus for tuning a PID controller. US Patent No. 7,035,695.