Laurence Bull David McG. Squire Jan Newmarch Yuliang Zheng Grouping Verifiable Content for Selective Disclosure. 1-12 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2727&spage=1 2003 conf/acisp/2003 ACISP db/conf/acisp/acisp2003.html#BullSNZ03