“…To obtain a sufficient condition, one can use global stability analysis, like Lyapunov's direct method (Belykh et al, 2006(Belykh et al, , 2005(Belykh et al, , 2004aChen, 2006Chen, , 2008Li et al, 2009;Chua, 1994, 1995a,b,c) or contraction theory (Aminzare and Sontag, 2015;Li et al, 2007;Lohmiller and Slotine, 1998;Pham and Slotine, 2007;Russo and Di Bernardo, 2009;Tabareau et al, 2010;Wang and Slotine, 2005).…”