Stefaan Seys Bart Preneel Efficient Cooperative Signatures: A Novel Authentication Scheme for Sensor Networks. 86-100 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3450&spage=86 2005 conf/spc/2005 SPC db/conf/spc/spc2005.html#SeysP05