diff -r 3351c85ffa02 -r 0274acee0e35 lemon/concept/undir_graph.h
--- a/lemon/concept/undir_graph.h	Tue Jun 07 16:11:23 2005 +0000
+++ b/lemon/concept/undir_graph.h	Tue Jun 07 16:12:14 2005 +0000
@@ -26,6 +26,7 @@
 #define LEMON_CONCEPT_UNDIR_GRAPH_H
 
 #include <lemon/concept/graph_component.h>
+#include <lemon/utility.h>
 
 namespace lemon {
   namespace concept {
@@ -233,6 +234,11 @@
 
     class UndirGraph {
     public:
+      ///\e
+
+      ///\todo undocumented
+      ///
+      typedef True UndirTag;
 
       /// Type describing a node in the graph
       typedef GraphNode Node;