Total and Partial Well-Founded Datalog Coincide. - Jörg Flum; Max Kubierschky; Bertram Ludäscher (ICDT, 1997)

Yet Another Hierarchy Theorem. - Max Kubierschky (J. Symb. Log., 2000)

Games and total Datalog¬ queries. - Jörg Flum; Max Kubierschky; Bertram Ludäscher (Theor. Comput. Sci., 2000)