A 4-D Hyperchaotic Memristive Dynamical System Dimitrios Prousalis, Christos Volos, Ioannis Stouboulos and Ioannis Kyprianidis MATEC Web Conf., 76 (2016) 02047 Published online: 21 October 2016 DOI: 10.1051/matecconf/20167602047