Didn't Panu M. \u00C5kerman and H\u00E4kkil\u00E4, J. not co-author a paper?
Was a paper not not co-authored by Panu M. \u00C5kerman and H\u00E4kkil\u00E4, J.?
ASK { ?x <https://dblp.org/rdf/schema#authoredBy> <https://dblp.org/pid/28/3152> . ?x <https://dblp.org/rdf/schema#authoredBy> <https://dblp.org/pid/62/6700> }
<https://dblp.org/pid/28/3152> <https://dblp.org/pid/62/6700>