diff -r 98b306776b25 -r 9147b013331a lemon/core.h
--- a/lemon/core.h	Fri Jun 22 16:31:05 2012 +0200
+++ b/lemon/core.h	Fri Aug 24 15:41:46 2012 +0200
@@ -1849,15 +1849,26 @@
     ///this operator. If you change the outgoing arcs of
     ///a single node \c n, then \ref refresh(Node) "refresh(n)" is enough.
     ///
-#ifdef DOXYGEN
-    Arc operator()(Node s, Node t, Arc prev=INVALID) const {}
-#else
-    using ArcLookUp<GR>::operator() ;
-    Arc operator()(Node s, Node t, Arc prev) const
+    Arc operator()(Node s, Node t, Arc prev=INVALID) const
     {
-      return prev==INVALID?(*this)(s,t):_next[prev];
+      if(prev==INVALID)
+        {
+          Arc f=INVALID;
+          Arc e;
+          for(e=_head[s];
+              e!=INVALID&&_g.target(e)!=t;
+              e = t < _g.target(e)?_left[e]:_right[e]) ;
+          while(e!=INVALID)
+            if(_g.target(e)==t)
+              {
+                f = e;
+                e = _left[e];
+              }
+            else e = _right[e];
+          return f;
+        }
+      else return _next[prev];
     }
-#endif
 
   };