Fábio Protti, Gerson Zaverucha. On the Relations between Acceptable Programs and Stratifiable Classes. In Flávio Moreira de Oliveira, editor, Advances in Artificial Intelligence, 14th Brazilian Symposium on Artificial Intelligence, SBIA 98, Porto Alegre, Brazil, November 4-6, 1998, Proceedings. Volume 1515 of Lecture Notes in Computer Science, pages 141-150, Springer, 1998.