Question: List the common prime minister of the Robert Ray and graham richardson ?
SPARQL query:
PREFIX onto: <http://dbpedia.org/ontology/>
SELECT DISTINCT ?uri WHERE { <http://dbpedia.org/resource/Robert_Ray_(Australian_politician)> onto:primeMinister ?uri. <http://dbpedia.org/resource/Graham_Richardson> onto:primeMinister ?uri . }