- CoRR (2005)
- CoRR (2010)
- CoRR (2009)
- CoRR (2002)
- CoRR (2011)
- J. Log. Program. 27(2):89-106 (1996)
- Web Intelligence, page 447-451. IEEE Computer Society, (2007)
- Theor. Comput. Sci. (1988)
- Semantic Techniques for the Web: The REWERSE Perspective, chapter 1, (2009)
- PPSWR, volume 3208 of Lecture Notes in Computer Science, page 1-18. Springer, (2004)
- PPSWR, volume 2901 of Lecture Notes in Computer Science, page 128-145. Springer, (2003)
- ICLP, volume 2237 of Lecture Notes in Computer Science, page 284-299. Springer, (2001)
- Electr. Notes Theor. Comput. Sci. 30(4):215-234 (1999)
- AMAST, volume 1548 of Lecture Notes in Computer Science, page 389-405. Springer, (1998)
- TPLP 2(4-5):549-610 (2002)
- New Generation Comput. 9(1):69-80 (1991)
- Acta Inf. 32(1):27-29 (1995)
- Acta Inf. 22(3):311-331 (1985)
- Acta Inf. 22(6):699-707 (1986)
- Knowl. Inf. Syst. 25(1):137-168 (2010)


author