1. An off-axis circle criterion for the stability of feedback systems with an monotonic nonlinearity.;Cho;IEEE Trans.,1968
2. Modified multivariable circle theorems.;Cook,1973
3. Conditions for the absence of limit cycles.;Cook;IEEE Trans.,1976
4. Feedback Systems: Input-Output Properties.;Desoer,1975
5. An off-axis multivariable circle stability criterion.;Harris;Proc IEE,1981