digraph g {
  rankdir = "TB";
  //bgcolor = "#e6e6e6";
  bgcolor = "transparent";
  article [ label="oa:articles/1", shape="box" ];
  proof1_5 [ label="oa:articles/1#proof5", shape="box" ];
  th1 [ label="oa:articles/1#theorem1", shape="box" ];

  article2 [ label="oa:articles/2", shape="box" ];
  lemma1 [ label="oa:articles/2#lemma1", shape="box" ];
  proof2_3 [ label="oa:articles/2#proof3", shape="box" ];

  article -> proof1_5 [ label="ns:contains" ] ;
  article -> th1 [ label="ns:contains" ] ;
  article2 -> proof2_3 [ label="ns:contains" ] ;
  article2 -> lemma1 [ label="ns:contains" ] ;
  proof1_5 -> th1 [ label="ns:proves" ];
  th1 -> "ns:Theorem" [ label="rdf:Type" ];

  proof2_3 -> lemma1 [ label="ns:proves" ] ;
  proof2_3 -> th1 [ label="ns:applies" ] ;

}