Finding the Artists that are married together

1       PREFIX mo:      &lt;http://purl.org/ontology/mo/&gt; 2       PREFIX rel:     &lt;http://purl.org/vocab/relationship/&gt; 3       PREFIX foaf:    &lt;http://xmlns.com/foaf/0.1/&gt; 4       SELECT ?artist1_name ?artist2_name 5       WHERE 6       { 7            ?artist1  a mo:MusicArtist; 8                     foaf:name ?artist1_name.

9          ?artist2 a mo:MusicArtist; 10                   foaf:name ?artist2_name.

11          ?artist1 rel:spouseOf ?artist2. 12      }