Jack Brassil, Larry O'Gorman, N.F. Maxemchuk, S.H. Low.
Electronic Marking and Identification Techniques to Discourage Document Copying, ftp.research.att.com Technical Document at AT&T Bell Research Laboratories.
10 pages.
ftp://ftp.research.att.com/dist/brassil/1994/infocom94a.ps.Z