Hiroaki Kikuchi Kensuke Abe Shohachiro Nakanishi Performance Evaluation of Certificate Revocation Using <i>k</i>-Valued Hash Tree. 103-117 1999 conf/isw/1999 ISW http://link.springer.de/link/service/series/0558/bibs/1729/17290103.htm db/conf/isw/isw1999.html#KikuchiAN99