Wibowo, B. S., B. R. Trilaksono, and A. Syaichu-Rohman. “H∞ Control of Polynomial Fuzzy Systems: A Sum of Squares Approach”. Journal of Engineering and Technological Sciences, vol. 46, no. 2, July 2014, pp. 152-69, doi:10.5614/j.eng.technol.sci.2014.46.2.3.