Was a paper not not co-authored by Efthymios Alepis and Maria Virvou?
Didn't Efthymios Alepis and Maria V. not co-author a paper?
ASK { ?x <https://dblp.org/rdf/schema#authoredBy> <https://dblp.org/pid/27/4432> . ?x <https://dblp.org/rdf/schema#authoredBy> <https://dblp.org/pid/35/2047> }
<https://dblp.org/pid/27/4432> <https://dblp.org/pid/35/2047>