PREFIX dc: <http://purl.org/dc/elements/1.1/>
PREFIX po: <http://purl.org/ontology/po/>
PREFIX timeline: <http://purl.org/NET/c4dm/timeline.owl#>
PREFIX event: <http://purl.org/NET/c4dm/event.owl#>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
SELECT DISTINCT ?episode ?title ?start
WHERE
{
    ?episode dc:title ?title;
        po:version ?version;
        a po:Episode.
    ?broadcast po:broadcast_of ?version;
        po:broadcasted_on <http://www.bbc.co.uk/bbcone#service>;
        po:schedule_date "2009-05-01"^^xsd:date;
        event:time ?timeline .
    ?timeline a timeline:Interval;
        timeline:start ?start.
}
ORDER BY ?start