sub:assertion {
  sub:get-presentations-by-speaker dct:description "Returns all presentations by a given speaker, with label, date, event, and nanopub link." ;
    dct:license <http://www.apache.org/licenses/LICENSE-2.0> ;
    a <https://w3id.org/kpxl/grlc/grlc-query> ;
    rdfs:label "Get presentations by speaker" ;
    <https://w3id.org/kpxl/grlc/endpoint> <https://w3id.org/np/l/nanopub-query-1.1/repo/type/3952cad1a6d2561f045d33e5e79c03e7264b0a492b8becf6c62656c596cf398c> ;
    <https://w3id.org/kpxl/grlc/sparql> """prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>
prefix dct: <http://purl.org/dc/terms/>
prefix np: <http://www.nanopub.org/nschema#>
prefix npa: <http://purl.org/nanopub/admin/>
prefix npx: <http://purl.org/nanopub/x/>
prefix wd: <http://www.wikidata.org/entity/>

select ?presentation ?presentation_label ?date ?event ?event_label ?np (\"^\" as ?np_label) where {
  graph npa:graph {
    ?np npa:hasValidSignatureForPublicKeyHash ?pubkey .
    filter not exists { ?npx npx:invalidates ?np ; npa:hasValidSignatureForPublicKeyHash ?pubkey . }
    filter not exists { ?np npx:hasNanopubType npx:ExampleNanopub . }
    ?np dct:created ?npdate .
    ?np np:hasAssertion ?a .
    ?np npx:introduces ?presentation .
  }
  graph ?a {
    ?presentation a wd:Q604733 .
    ?presentation wd:P823 ?_speaker_iri .
    optional { ?presentation rdfs:label ?presentation_label . }
    optional { ?presentation dct:date ?date . }
    optional {
      ?presentation dct:isPartOf ?event .
      optional { ?event rdfs:label ?event_label . }
    }
  }
} order by desc(?date)""" .
}