1. “Automatic tuning of simple regulators with specifications on phase and amplitude margins.”;Åström;Automatica,1984
2. Automatic Tunings of PID Controllers;Åström,1988
3. Bengtsson, G. and B. Egardt (1984): “Experiences with self-tuning control in the process industry.” In Preprints 9th IFAC World Congress, Budapest, Hungary.
4. “Theoretical consideration of retarded control.”;Cohen;Trans. ASME,1953
5. “Refinements of the Ziegler-Nichols tuning formula.”;Hang;IEE Proceedings-D,1991