T. Eiter, W. Faber, N. Leone, G. Pfeifer, A. Polleres:
"A Logic Programming Approach to Knowledge-State Planning: Semantics and Complexity";
ACM Transactions on Computational Logic, 5 (2004), 2; 206 - 263.
http://aleph.ub.tuwien.ac.at/F?base=tuw01&func=find-c&ccl_term=AC04968515