PREFIX dc: <http://purl.org/dc/elements/1.1/>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX : <http://example.org/book/>
PREFIX foaf: <http://xmlns.com/foaf/0.1/>

select * where {
  {
    ?x foaf:mbox <mailto:alice@example> .
    ?x ^foaf:knows/foaf:name ?name .
  }
} limit 100
