Question: Which suppliers did the Waltham Forest Council utilize for recycling?
SPARQL:
 select distinct(?supplier) as ?result from <http://linkedspending.aksw.org/uk-local-walthamforest> { ?obs qb:dataSet ls:uk-local-walthamforest. ?obs lso:uk-local-walthamforest-ExpenseType "RECYCLING". ?obs lso:uk-local-walthamforest-to ?supplier. }