Josef Pieprzyk Huaxiong Wang Chaoping Xing Multiple-Time Signature Schemes against Adaptive Chosen Message Attacks. 88-100 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3006&spage=88 2003 conf/sacrypt/2003 Selected Areas in Cryptography db/conf/sacrypt/sacrypt2003.html#PieprzykWX03