Iñaki Goirizelaia Maider Huarte Juanjo Unzilla Ted Selker An Optical Scan E-Voting System based on N-Version Programming. 47-53 2008 6 IEEE Security & Privacy 3 http://doi.ieeecomputersociety.org/10.1109/MSP.2008.57 db/journals/ieeesp/ieeesp6.html#GoirizelaiaHUS08