{

                   [ a rdf:Statement ; rdf:subject ?x ; 
                        rdf:predicate d:influencedBy ; 
                        rdf:object d:Welles 
                   ] d:significance "0.7"^^xsd:decimal .
}


##
PREFIX d: <http://dbpedia.org/ontology/> 
SELECT ?x 
WHERE { <<?x d:influencedBy d:Welles>> d:significance ?sig . 
                 FILTER (?sig > 0.7) 
              }

## Versus 
## What exists

PREFIX d: <http://dbpedia.org/ontology/> 
SELECT ?x 
WHERE { 
                   [ a rdf:Statement ; rdf:subject ?x ; 
                        rdf:predicate d:influencedBy ; 
                        rdf:object d:Welles 
                   ] d:significance ?sig .
                   FILTER (?sig > 0.7) 
                 }