Question: Top 3 IW Council Spending service areas?
SPARQL:
 select ?result from <http://linkedspending.aksw.org/iw-council-spending-2012-13-test> { ?obs qb:dataSet ls:iw-council-spending-2012-13-test. ?obs lso:iw-council-spending-2012-13-test-servicearea ?result. ?obs lso:iw-council-spending-2012-13-test-amount ?amount. } order by desc(sum(xsd:decimal(?amount))) limit 3