E. Roșu, M. Găiceanu, I. Bivol, and D. Călueanu, “Energetic Optimal Control Of Adjustable Drive Systems”, The Annals of “Dunarea de Jos“ University of Galati. Fascicle III, Electrotechnics, Electronics, Automatic Control, Informatics, vol. 25, pp. 61-70, Oct. 2002.