1. Alferes, J. J., Damásio, C. V., and Pereira, L. M.: SLX?A top-down derivation procedure for programs with explicit negation, in M. Bruynooghe (ed.),ILPS, MIT Press, 1994 (to appear).
2. Alferes, J. J., Damásio, C. V., and Pereira, L. M.: Top-down query evaluation for well-founded semantics with explicit negation, in A. Cohn (ed.),Proc. ECAI'94, Morgan Kaufmann, 1994, pp. 140?144.
3. Alferes, J. J. and Pereira, L. M.: On logic program semantics with two kinds of negation, in K. Apt (ed.),Int. Joint Conf. and Symp. on LP, MIT Press, 1992, pp. 574?588.
4. Alferes, J. J. and Pereira, L. M.: Belief, provability, and logic programs, in C. MacNish, D. Pearce, and L. M. Pereira (eds),JELIA'94, Lecture Notes in AI 838 (798), Springer-Verlag, 1994, pp. 106?121.
5. Alferes, J. J. and Pereira, L. M.: Contradiction: When avoidance equals removal, in R. Dyckhoff (ed.),4th Int. Ws. on Extensions of LP, Lecture Notes in AI 839 (798), Springer-Verlag, 1994.