Ingo Melzer Mario Jeckle Using Corporate Firewalls for Web Services Trust. 79-87 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2853&spage=79 2003 conf/icws/2003e ICWS-Europe db/conf/icws/icwse2003.html#MelzerJ03