Alessandro Cilardo Antonino Mazzeo Luigi Romano Giacinto Paolo Saggese Giuseppe Cattaneo Using Web Services Technology for Inter-enterprise Integration of Digital Time Stamping. 960-974 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2889&spage=960 2003 conf/otm/2003 OTM Workshops db/conf/otm/otm2003.html#CilardoMRSC03