“THE IMPROVEMENT MADE BY THE NONLINEAR PROPORTIONAL INTEGRAL CONTROLLER COMPARED TO THE VARIABLE GAIN PROPORTIONAL INTEGRAL CONTROLLER: N a”. REVUE ROUMAINE DES SCIENCES TECHNIQUES — SÉRIE ÉLECTROTECHNIQUE ET ÉNERGÉTIQUE, vol. 68, no. 2, July 2023, pp. 158-63, https://doi.org/10.59277/RRST-EE.2023.68.2.7.