1. Nonlinear H∞ control theory: A literature survey;Ball,1989
2. Subharmonic functions and performance bounds on linear time-variant feedback systems;Boyd,1984
3. A Course in Functional Analysis;Conway,1985
4. Nonlinear unity feedback systems and Q-parameterization;Desoer,1984
5. Feedback Systems: Input-Output Properties;Desoer,1975