Georgios Kambourakis Angelos N. Rouskas Stefanos Gritzalis Inter/Intra Core Network Security with PKI for 3G-and-Beyond Systems. 13-24 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3042&spage=13 2004 conf/networking/2004 NETWORKING db/conf/networking/networking2004.html#KambourakisRG04