Philip DesAutels; et al. <a href="http://www.w3.org/TR/1998/REC-DSig-label-19980527"><cite>PICS Signed Labels (DSig) 1.0 Specification.</cite></a> 27 May 1998. W3C Recommendation. URL: <a href="http://www.w3.org/TR/1998/REC-DSig-label-19980527">http://www.w3.org/TR/1998/REC-DSig-label-19980527</a>