“…For more specialized work, which consist of results on observers for sampled-data nonlinear systems [10], discrete-time sliding mode observers [12], discrete-time nonlinear systems [13], observers for Lipschitz nonlinear systems [8,13,14,16], and Lipschitz nonlinear discrete-time systems with time-delay [15]. Observer design for nonlinear systems with unknown inputs [17][18][19][20], switching nonlinear systems [21], one-sided Lipschitz nonlinear systems [22,23], and so on.…”