This author has not been identified. Look up 'Efstratios Kontopoulos' in GoogleThis author has not been identified. Look up 'Dimitris Vrakas' in GoogleThis author has not been identified. Look up 'Fotis Kokkoras' in GoogleThis author has not been identified. It may be one of the following persons: Look up 'Nick Bassiliades' in GoogleThis author has not been identified. Look up 'Ioannis P. Vlahavas' in Google