PREFIX pubann:<http://pubannotation.org/ontology/>
SELECT ?s1 ?s2
WHERE {
  GRAPH prj:GlycoBiology-Epitope {
    ?o1 tao:denoted_by ?s1 .
  }

  GRAPH prj:GlycoBiology-MAT {
    ?o2 tao:denoted_by ?s2 .
  }

  ?o3 tao:denoted_by ?s3 .
  ?o3 a pubann:Sentence .
  ?s3 tao:contains ?s1 .
  ?s3 tao:contains ?s2 .
}