Distinct(Project(BGP( ?s ?p ?o .
                      ?o <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <https://w3id.org/i40/sto#Standard> .
                      ?s <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <https://w3id.org/i40/sto#Standard>),
                 {?p}))