CONSTRUCT ... ORDER BY

[Laura Morales]

I'm running this query


    CONSTRUCT { ?sbj ex:property ?obj }
    FROM <...>
    WHERE {
      ?sbj a [] ;
           ex:property ?obj .
    }
    ORDER BY ?obj


but the results are not returned sorted. Actually, it looks like the results 
are sorted by ?sbj instead. What am I doing wrong?