1. Absolute stability of nonlinear control systems of automatic control;Popov;Automation and Remote Control,1962
2. Algebraic criteria for absolute stability, optimality, and passivity of dynamic systems;Šiljak;IEE Proc.,1970
3. New algebraic criteria for positive realness;Šiljak;J. Franklin Inst.,1971
4. Frequency Domain Criteria for Absolute Stability;Narendra,1973
5. Adaptive Control—The Model Reference Approach;Landau,1979