Question: Give me all people with first name Jimmy.
SPARQL query:
PREFIX foaf: <http://xmlns.com/foaf/0.1/>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
SELECT DISTINCT ?uri ?string 
WHERE {
	?uri rdf:type foaf:Person.       
        ?uri foaf:givenName 'Jimmy'@en   .
        OPTIONAL { ?uri rdfs:label ?string . FILTER (lang(?string) = 'en') }
}