When was the research paper on -b by Royal Institute of Technology published?
Royal Institute of Technology, Stockholm, Sweden published a paper on -b in what year?
SELECT DISTINCT ?answer WHERE { <https://dblp.org/rec/journals/eccc/ECCC-TR99-039> <https://dblp.org/rdf/schema#authoredBy> ?x . ?x <https://dblp.org/rdf/schema#primaryAffiliation> 'Royal Institute of Technology, Stockholm, Sweden' . <https://dblp.org/rec/journals/eccc/ECCC-TR99-039> <https://dblp.org/rdf/schema#yearOfPublication> ?answer }
<https://dblp.org/rec/journals/eccc/ECCC-TR99-039>