R. M.Z.A, H. M.N.A, Y. Z.N.M, and S. S.N.M, “Parametric Study for Vibration Energy Harvester System”, IJET, vol. 7, no. 4.38, pp. 1647–1650, Dec. 2018, doi: 10.14419/ijet.v7i4.38.29224.