Foto N. Afrati Christos H. Papadimitriou George Papageorgiou Athena Roussou Yehoshua Sagiv Jeffrey D. Ullman On the Convergence of Query Evaluation. 341-359 1989 38 J. Comput. Syst. Sci. 2 db/journals/jcss/jcss38.html#AfratiPPRSU89