Finding people that sell a musical manifestation and finding people wanting that musical manifestation

From Music Ontology Wiki

 1    PREFIX mo:   <http://purl.org/ontology/mo/>
 2    PREFIX foaf: <http://xmlns.com/foaf/0.1/>        
 3    SELECT ?name_seller ?name_buyer
 4    WHERE 
 5    {
 6        {
 7            ?seller a foaf: Person;
 8                    foaf:name ?name_seller;
 9                    mo:sell_item <http://zitgist.com/music/record/a89e1d92-5381-4dab-ba51-733137d0e431>.
 10       }
 11       UNION
 12       {
 13           ?seller a foaf: Person;
 14                   foaf:name ?name_seller;
 15                   mo:exchange_item <http://zitgist.com/music/record/a89e1d92-5381-4dab-ba51-733137d0e431>.
 16       }
 17       UNION
 18       {    
 19           ?buyer a foaf: Person;
 20                  foaf:name ?name_buyer;
 21                  mo:want_item <http://zitgist.com/music/record/a89e1d92-5381-4dab-ba51-733137d0e431>.
 22       }
 23   }