Optimal Gain and Phase Margin Tuning for PID Controllers. - Weng Khuen Ho; Khiang Wee Lim; Wen Xu 003 (Autom., 1998)

The direct Nyquist array design of PID controllers. - Weng Khuen Ho; Tong Heng Lee; Wen Xu 003; J. R. Zhou; Ee Beng Tay (IEEE Trans. Ind. Electron., 2000)