Question: How many rivers are crossed by different Box Girder bridges?
SPARQL query:
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX prop: <http://dbpedia.org/property/>
PREFIX onto: <http://dbpedia.org/ontology/>
SELECT DISTINCT COUNT(?uri) WHERE { ?x prop:design <http://dbpedia.org/resource/Box_girder_bridge> . ?x prop:crosses ?uri . ?uri rdf:type onto:River}