Multiple solutions and corresponding power output of a nonlinear bistable piezoelectric energy harvester Arkadiusz Syta, Grzegorz Litak, Michael I. Friswell and Sondipon Adhikari Eur. Phys. J. B, 89 4 (2016) 99 Published online: 13 April 2016 DOI: 10.1140/epjb/e2016-60699-0