Hi. Please, I need suggestions of simple materials on nonlinear controller design methods for systems represented by nonlinear state equations. The specific techniques are backstepping, "Adding A Power Integrator" technique, finite-time stabilization, nonlinear state feedback controller design, nonlinear controller design for systems with unmeasurable states & nonlinear adaptive control for systems with unknown parameters. Please, I will be most appreciative if relatively simple books/texts can be suggested for each of these. Thanks a lot.