Load frequency control of a three-area power system based on the optimal tuning of a fractional-order proportional–integral–derivative controller with multi-objective gray wolf optimization - Prabakaran, R.; Kanimozhi, R.; Ayyappan, B. Prakash; Thanigaiselvan, R. (Maǧallaẗ al-abḥath al-handasiyyaẗ, 2023)