“…In view of their usefulness also for control purposes, see e.g. Blanchini (1995) and Clarke, Ledyaev, Rifford, and Stern (2000), many researches have been carried out recently on the explicit construction of Lyapunov functions; for critical systems recent results are reported in Fu (1992Fu ( , 2000a, Fu and Abed (1993) and Schwartz and Yan (1995) whereas other related results (some of which are concerned with robustness issues) are in Blanchini (1995), Parrilo (2000), Papachristodouiou and Prajna (2002), Chesi, Garulli, Tesi, and Vicino (2003), Gle´ria, Figueiredo, and Rocha Filho (2003), Chesi (2004), Bouzaouache and Braiek (2008) and Chesi and Hung (2008). In many cases, e.g.…”