Spyros G. Tzafestas Gerasimos G. Rigatos G. A. Vagelatos Design of fuzzy gain-scheduled robust controllers using Kharitonov's extremal gain margin theorem. 39-56 2001 10 Journal of Intelligent and Fuzzy Systems 1 http://iospress.metapress.com/content/qtyyf0lhval08egj/ db/journals/jifs/jifs10.html#TzafestasRV01