# filename: cap5example20.rq

PREFIX dbo: <http://dbpedia.org/ontology/>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX dc: <http://purl.org/dc/elements/1.1/description#>
SELECT *
FROM <http://dbpedia.org/data/Santiago_Ram%C3%B3n_y_Cajal.rdf>
FROM <http://dbpedia.org/data/Albert_Einstein.rdf>
FROM <http://dbpedia.org/data/Severo_Ochoa.rdf>
WHERE {
     ?cientifico dbo:birthDate ?nacio .
     ?cientifico dbo:deathDate ?murio .
     OPTIONAL {
       ?cientifico dbo:knownFor ?campo .
     }
     ?cientifico rdf:type dbo:Scientist
}
ORDER BY ?cientifico 