Françoise Levy-dit-Vehel Ludovic Perret Attacks on Public Key Cryptosystems Based on Free Partially Commutative Monoids and Groups. 275-289 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3348&spage=275 2004 conf/indocrypt/2004 INDOCRYPT db/conf/indocrypt/indocrypt2004.html#Levy-dit-VehelP04