M.-C. CHIU, Y.-C. CHANG, L.-J. YEH, and C.-H. CHUNG, “Numerical Assessment of a One-Mass Spring-Based Electromagnetic Energy Harvester on a Vibrating Object”, Arch. Acoust., vol. 41, no. 1, pp. 119–131, Nov. 2015, doi: 10.1515/aoa-2016-0012.