Question: Which U.S. State has the abbreviation MN?
SPARQL:
PREFIX dbp: <http://dbpedia.org/property/>
PREFIX res: <http://dbpedia.org/resource/>
PREFIX yago: <http://dbpedia.org/class/yago/>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
SELECT ?uri ?string WHERE 
{
	?uri rdf:type yago:StatesOfTheUnitedStates .
        ?uri dbp:postalabbreviation 'MN'@en .
	OPTIONAL { ?uri rdfs:label ?string. FILTER (lang(?string) = 'en') }
}