PREFIX rdf:   <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX foaf:  <http://xmlns.com/foaf/0.1/>
PREFIX bench: <http://localhost/vocabulary/bench/>
PREFIX dc:    <http://purl.org/dc/elements/1.1/>

ASK {
  ?article rdf:type bench:Article .
  ?article dc:creator ?person1 .
  ?inproc  rdf:type bench:Inproceedings .
  ?inproc  dc:creator ?person2 .
  ?person1 foaf:name ?name1 .
  ?person2 foaf:name ?name2
  FILTER (?name1=?name2)
}