We propose a description-logic style extension of OWL DL, which includes DL-safe variable SWRL and seamlessly integrates datalog rules. Our language also sports a tractable fragment, which we call ELP 2, covering OWL EL, OWL RL, most of OWL QL, and variable restricted datalog.
Krisnadhi, A. A.,
& Hitzler, P.
(2010). Nominal Schemas for Integrating Rules and Ontologies. Kno.e.sis Center Technical Report.