combining algorithm paper

The paper we are discussing is available from:
   https://www.cerias.purdue.edu/assets/pdf/bibtex_archive/2008-9-report.pdf

There is an update to this paper on ACM that has some significant
changes, however the main points remain primarily intact:
There are details on where this paper appeared and access info at end:


Access Control Policy Combining: Theory Meets Practice

Ninghui Li, Qihua Wang, Wahbeh Qardaji, Elisa Bertino, Prathima Rao
Purdue University, Department of Computer Science
305 N. University Street, West Lafayette, IN 47907,USA
{ninghui, qwang, wqardaji, bertino, prao}@cs.purdue.edu
Jorge Lobo
IBM T.J. Watson Research
Center
Hawthorne, NY, USA

Dan Lin
Missouri University of Science
and Technology
500 West 15th Street, Rolla,
MO 65409



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SACMAT’09, June 3–5, 2009, Stresa, Italy.
Copyright 2009 ACM 978-1-60558-537-6/09/06 ...$5.00.