In which venue did Paul publish the paper about Trace languages?
Gastin published the paper on Trace languages in which venue?
SELECT DISTINCT ?answer WHERE { <https://dblp.org/rec/conf/mfcs/DiekertGP91> <https://dblp.org/rdf/schema#authoredBy> <https://dblp.org/pid/g/PaulGastin> . <https://dblp.org/rec/conf/mfcs/DiekertGP91> <https://dblp.org/rdf/schema#publishedIn> ?answer }
<https://dblp.org/pid/g/PaulGastin> <https://dblp.org/rec/conf/mfcs/DiekertGP91>