Marie Henderson Robert S. Coulter Ed Dawson Eiji Okamoto Modelling Trust Structures for Public Key Infrastructures. 56-70 2002 conf/acisp/2002 ACISP http://link.springer.de/link/service/series/0558/bibs/2384/23840056.htm db/conf/acisp/acisp2002.html#HendersonCDO02