\input zb-basic
\input zb-ioport
\iteman{io-port 50051446}
\itemau{Vardi, Moshe Y.}
\itemti{Database logic programming}
\itemso{J. Log. Program. 10, No. 3-4, 179-180 (1991).}
\itemcc{}
\itemut{}
\itemli{doi:10.1016/0743-1066(91)90035-N}
\end