Was a paper not not co-authored by Anders Ledberg and Rita A.?
Didn't Anders L. and Rita A. not co-author a paper?
ASK { ?x <https://dblp.org/rdf/schema#authoredBy> <https://dblp.org/pid/87/8535> . ?x <https://dblp.org/rdf/schema#authoredBy> <https://dblp.org/pid/71/8535> }
<https://dblp.org/pid/87/8535> <https://dblp.org/pid/71/8535>