# QUERY 2 to get the graph around warfarin with of length <= 4
PREFIX pharmgkb: <http://bio2rdf.org/pharmgkb:>
CONSTRUCT {pharmgkb:PA451906 ?p1 ?o1.
          ?o1 ?p2 ?o2.
          ?o2 ?p3 ?o3.
          ?o3 ?p4 ?o4.
          } 
WHERE {pharmgkb:PA451906 ?p1 ?o1.
      OPTIONAL{?o1 ?p2 ?o2. 
               OPTIONAL{?o2 ?p3 ?o3.
                        OPTIONAL{?o3 ?p4 ?o4.}
       	}	}	}