1. Simple method for tuning SISO controllers in multivariable systems
2. Automatic tuning of simple regulators with specifications on phase and amplitude margins
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4. Wadey, M.D. and Atherton, D.P. “Periodic Modes in Multivariable Systyem with Relay and Saturation Elements”, In Proc. Symp. on application of multivariable system techniques, Plymouth, UK, 1984.