Panagiotis Papadakos Giorgos Vasiliadis Yannis Theoharis Nikos Armenatzoglou Stella Kopidaki Yannis Marketakis Manos Daskalakis Kostas Karamaroudis Giorgos Linardakis Giannis Makrydakis Vangelis Papathanasiou Lefteris Sardis Petros Tsialiamanis Georgia Troullinou Kostas Vandikas Dimitris Velegrakis Yannis Tzitzikas http://arxiv.org/abs/0803.2220 2008 CoRR abs/0803.2220 db/journals/corr/corr0803.html#abs-0803-2220 informal publication