Electromagnetic rolling mass wave energy harvester for oceanic drifter applications Matias Carandell, Jiri Tichy, Jan Smilek, Daniel Mihai Toma, Manel Gasulla, Joaquín del Río and Zdenek Hadas Eur. Phys. J. Spec. Top., 231 8 (2022) 1475-1484 Published online: 05 March 2022 DOI: 10.1140/epjs/s11734-022-00499-5