Marcus Lippert Vangelis Karatsiolis Alexander Wiesmaier Johannes Buchmann Life-cycle management of X.509 certificates based on LDAP directories. 419-439 2006 14 Journal of Computer Security 5 http://iospress.metapress.com/openurl.asp?genre=article&issn=0926-227X&volume=14&issue=5&spage=419 db/journals/jcs/jcs14.html#LippertKWB06