Roberto Di Pietro Gianluigi Me Maurizio Adriano Strangio A Two-Factor Mobile Authentication Scheme for Secure Financial Transactions. 28-34 2005 conf/icmb/2005 ICMB http://doi.ieeecomputersociety.org/10.1109/ICMB.2005.12 db/conf/icmb/icmb2005.html#PietroMS05