“…Lyapunov's method was suggested in lieu of a gradient descent approach as in (1), and ended up as the foundation for stability of adaptive systems. Several seminal results were published during this period which witnessed several surveys by Lindorff and Carroll [38], Landau [39], Wittenmark [40], Unbehauen [41], and others [42,43,44]. These were followed by edited books such as [45,46,47], and subsequent textbooks in deterministic and continuous-time [48,49,50,51,52,53,54], stochastic systems in books and papers such as [55,56,57,58], and multiple-input, multiple-output systems in [52].…”