J. Oetsch, M. Seidl, H. Tompits, S. Woltran:
"Testing Relativised Uniform Equivalence under Answer-Set Projection in the System ccT";
in: "Applications of Declarative Programming and Knowledge Management", D. Seipel, M. Hanus, A. Wolf (ed.); Springer, 2009, ISBN: 978-3-642-00674-6, 241 - 246.
http://publik.tuwien.ac.at/files/PubDat_177140.pdf