prefix : <http://example.org/>
prefix xsd: <http://www.w3.org/2001/XMLSchema#>

:Person {
    :name xsd:string ;
    :age  xsd:integer;
    :worksFor @:Organization ? ;
    :knows @:Person *
}

:Organization {
    :name xsd:string ;
    :address xsd:string ? ;
}
