diff --git a/lemon/cycle_canceling.h b/lemon/cycle_canceling.h
--- a/lemon/cycle_canceling.h
+++ b/lemon/cycle_canceling.h
@@ -65,7 +65,8 @@
   /// \tparam C The number type used for costs and potentials in the
   /// algorithm. By default, it is the same as \c V.
   ///
-  /// \warning Both number types must be signed and all input data must
+  /// \warning Both \c V and \c C must be signed number types.
+  /// \warning All input data (capacities, supply values, and costs) must
   /// be integer.
   /// \warning This algorithm does not support negative costs for such
   /// arcs that have infinite upper bound.