PREFIX cpr: <http://purl.org/cpr/0.5#>
PREFIX ex: <http://www.example.org/grddl-primer#>
PREFIX skos: <http://www.w3.org/2004/02/skos/core#>
SELECT ?sign ?image

FROM <http://www.w3.org/TR/grddl-primer/hl7-sample-plus-owl.rdf>

WHERE {
  ?image a ex:DiagnosingImage;
         ex:indicates [ skos:prefLabel ?sign ]
}