Was a paper not not co-authored by Ingo S. and Jens S.?
Didn't Ingo S. and Jens Sch\u00F6nherr not co-author a paper?
ASK { ?x <https://dblp.org/rdf/schema#authoredBy> <https://dblp.org/pid/11/1807> . ?x <https://dblp.org/rdf/schema#authoredBy> <https://dblp.org/pid/71/1103> }
<https://dblp.org/pid/11/1807> <https://dblp.org/pid/71/1103>