'digraph mainmap {
URL = "gen.map.4.1.html"; 
 graph [ rankdir="TB" ]
 node [ shape="oval" ]
 edge [ color="grey" ]
 "source" [ URL="gen.map.4.2.html" ]
 "destination"
 "source" -> "destination" [ URL="gen.map.4.3.html" ]
}
'
