Was a paper not not co-authored by Thomas Christaller and Alois C. Knoll?
Didn't Thomas Christaller and Knoll, Alois C. not co-author a paper?
ASK { ?x <https://dblp.org/rdf/schema#authoredBy> <https://dblp.org/pid/c/TChristaller> . ?x <https://dblp.org/rdf/schema#authoredBy> <https://dblp.org/pid/k/AloisKnoll> }
<https://dblp.org/pid/c/TChristaller> <https://dblp.org/pid/k/AloisKnoll>