diff --git a/lemon/lgf_reader.h b/lemon/lgf_reader.h
--- a/lemon/lgf_reader.h
+++ b/lemon/lgf_reader.h
@@ -391,15 +391,37 @@
   template <typename Digraph>
   class DigraphReader;
 
+  /// \brief Return a \ref DigraphReader class
+  ///
+  /// This function just returns a \ref DigraphReader class.
+  /// \relates DigraphReader
   template <typename Digraph>
   DigraphReader<Digraph> digraphReader(Digraph& digraph,
-                                       std::istream& is = std::cin);
-
+                                       std::istream& is = std::cin) {
+    DigraphReader<Digraph> tmp(digraph, is);
+    return tmp;
+  }
+
+  /// \brief Return a \ref DigraphReader class
+  ///
+  /// This function just returns a \ref DigraphReader class.
+  /// \relates DigraphReader
   template <typename Digraph>
-  DigraphReader<Digraph> digraphReader(Digraph& digraph, const std::string& fn);
-
+  DigraphReader<Digraph> digraphReader(Digraph& digraph,
+                                       const std::string& fn) {
+    DigraphReader<Digraph> tmp(digraph, fn);
+    return tmp;
+  }
+
+  /// \brief Return a \ref DigraphReader class
+  ///
+  /// This function just returns a \ref DigraphReader class.
+  /// \relates DigraphReader
   template <typename Digraph>
-  DigraphReader<Digraph> digraphReader(Digraph& digraph, const char *fn);
+  DigraphReader<Digraph> digraphReader(Digraph& digraph, const char* fn) {
+    DigraphReader<Digraph> tmp(digraph, fn);
+    return tmp;
+  }
 
   /// \ingroup lemon_io
   ///
@@ -1189,51 +1211,39 @@
 
   };
 
-  /// \brief Return a \ref DigraphReader class
+  template <typename Graph>
+  class GraphReader;
+
+  /// \brief Return a \ref GraphReader class
   ///
-  /// This function just returns a \ref DigraphReader class.
-  /// \relates DigraphReader
-  template <typename Digraph>
-  DigraphReader<Digraph> digraphReader(Digraph& digraph,
-                                       std::istream& is = std::cin) {
-    DigraphReader<Digraph> tmp(digraph, is);
+  /// This function just returns a \ref GraphReader class.
+  /// \relates GraphReader
+  template <typename Graph>
+  GraphReader<Graph> graphReader(Graph& graph, std::istream& is = std::cin) {
+    GraphReader<Graph> tmp(graph, is);
     return tmp;
   }
 
-  /// \brief Return a \ref DigraphReader class
+  /// \brief Return a \ref GraphReader class
   ///
-  /// This function just returns a \ref DigraphReader class.
-  /// \relates DigraphReader
-  template <typename Digraph>
-  DigraphReader<Digraph> digraphReader(Digraph& digraph,
-                                       const std::string& fn) {
-    DigraphReader<Digraph> tmp(digraph, fn);
+  /// This function just returns a \ref GraphReader class.
+  /// \relates GraphReader
+  template <typename Graph>
+  GraphReader<Graph> graphReader(Graph& graph, const std::string& fn) {
+    GraphReader<Graph> tmp(graph, fn);
     return tmp;
   }
 
-  /// \brief Return a \ref DigraphReader class
+  /// \brief Return a \ref GraphReader class
   ///
-  /// This function just returns a \ref DigraphReader class.
-  /// \relates DigraphReader
-  template <typename Digraph>
-  DigraphReader<Digraph> digraphReader(Digraph& digraph, const char* fn) {
-    DigraphReader<Digraph> tmp(digraph, fn);
+  /// This function just returns a \ref GraphReader class.
+  /// \relates GraphReader
+  template <typename Graph>
+  GraphReader<Graph> graphReader(Graph& graph, const char* fn) {
+    GraphReader<Graph> tmp(graph, fn);
     return tmp;
   }
 
-  template <typename Graph>
-  class GraphReader;
-
-  template <typename Graph>
-  GraphReader<Graph> graphReader(Graph& graph,
-                                 std::istream& is = std::cin);
-
-  template <typename Graph>
-  GraphReader<Graph> graphReader(Graph& graph, const std::string& fn);
-
-  template <typename Graph>
-  GraphReader<Graph> graphReader(Graph& graph, const char *fn);
-
   /// \ingroup lemon_io
   ///
   /// \brief \ref lgf-format "LGF" reader for undirected graphs
@@ -2031,36 +2041,6 @@
 
   };
 
-  /// \brief Return a \ref GraphReader class
-  ///
-  /// This function just returns a \ref GraphReader class.
-  /// \relates GraphReader
-  template <typename Graph>
-  GraphReader<Graph> graphReader(Graph& graph, std::istream& is = std::cin) {
-    GraphReader<Graph> tmp(graph, is);
-    return tmp;
-  }
-
-  /// \brief Return a \ref GraphReader class
-  ///
-  /// This function just returns a \ref GraphReader class.
-  /// \relates GraphReader
-  template <typename Graph>
-  GraphReader<Graph> graphReader(Graph& graph, const std::string& fn) {
-    GraphReader<Graph> tmp(graph, fn);
-    return tmp;
-  }
-
-  /// \brief Return a \ref GraphReader class
-  ///
-  /// This function just returns a \ref GraphReader class.
-  /// \relates GraphReader
-  template <typename Graph>
-  GraphReader<Graph> graphReader(Graph& graph, const char* fn) {
-    GraphReader<Graph> tmp(graph, fn);
-    return tmp;
-  }
-
   class SectionReader;
 
   SectionReader sectionReader(std::istream& is);
diff --git a/lemon/lgf_writer.h b/lemon/lgf_writer.h
--- a/lemon/lgf_writer.h
+++ b/lemon/lgf_writer.h
@@ -351,17 +351,38 @@
   template <typename Digraph>
   class DigraphWriter;
 
+  /// \brief Return a \ref DigraphWriter class
+  ///
+  /// This function just returns a \ref DigraphWriter class.
+  /// \relates DigraphWriter
   template <typename Digraph>
   DigraphWriter<Digraph> digraphWriter(const Digraph& digraph,
-                                       std::ostream& os = std::cout);
+                                       std::ostream& os = std::cout) {
+    DigraphWriter<Digraph> tmp(digraph, os);
+    return tmp;
+  }
 
+  /// \brief Return a \ref DigraphWriter class
+  ///
+  /// This function just returns a \ref DigraphWriter class.
+  /// \relates DigraphWriter
   template <typename Digraph>
   DigraphWriter<Digraph> digraphWriter(const Digraph& digraph,
-                                       const std::string& fn);
+                                       const std::string& fn) {
+    DigraphWriter<Digraph> tmp(digraph, fn);
+    return tmp;
+  }
 
+  /// \brief Return a \ref DigraphWriter class
+  ///
+  /// This function just returns a \ref DigraphWriter class.
+  /// \relates DigraphWriter
   template <typename Digraph>
   DigraphWriter<Digraph> digraphWriter(const Digraph& digraph,
-                                       const char *fn);
+                                       const char* fn) {
+    DigraphWriter<Digraph> tmp(digraph, fn);
+    return tmp;
+  }
 
   /// \ingroup lemon_io
   ///
@@ -913,52 +934,40 @@
     /// @}
   };
 
-  /// \brief Return a \ref DigraphWriter class
+  template <typename Graph>
+  class GraphWriter;
+
+  /// \brief Return a \ref GraphWriter class
   ///
-  /// This function just returns a \ref DigraphWriter class.
-  /// \relates DigraphWriter
-  template <typename Digraph>
-  DigraphWriter<Digraph> digraphWriter(const Digraph& digraph,
-                                       std::ostream& os = std::cout) {
-    DigraphWriter<Digraph> tmp(digraph, os);
+  /// This function just returns a \ref GraphWriter class.
+  /// \relates GraphWriter
+  template <typename Graph>
+  GraphWriter<Graph> graphWriter(const Graph& graph,
+                                 std::ostream& os = std::cout) {
+    GraphWriter<Graph> tmp(graph, os);
     return tmp;
   }
 
-  /// \brief Return a \ref DigraphWriter class
+  /// \brief Return a \ref GraphWriter class
   ///
-  /// This function just returns a \ref DigraphWriter class.
-  /// \relates DigraphWriter
-  template <typename Digraph>
-  DigraphWriter<Digraph> digraphWriter(const Digraph& digraph,
-                                       const std::string& fn) {
-    DigraphWriter<Digraph> tmp(digraph, fn);
+  /// This function just returns a \ref GraphWriter class.
+  /// \relates GraphWriter
+  template <typename Graph>
+  GraphWriter<Graph> graphWriter(const Graph& graph, const std::string& fn) {
+    GraphWriter<Graph> tmp(graph, fn);
     return tmp;
   }
 
-  /// \brief Return a \ref DigraphWriter class
+  /// \brief Return a \ref GraphWriter class
   ///
-  /// This function just returns a \ref DigraphWriter class.
-  /// \relates DigraphWriter
-  template <typename Digraph>
-  DigraphWriter<Digraph> digraphWriter(const Digraph& digraph,
-                                       const char* fn) {
-    DigraphWriter<Digraph> tmp(digraph, fn);
+  /// This function just returns a \ref GraphWriter class.
+  /// \relates GraphWriter
+  template <typename Graph>
+  GraphWriter<Graph> graphWriter(const Graph& graph, const char* fn) {
+    GraphWriter<Graph> tmp(graph, fn);
     return tmp;
   }
 
-  template <typename Graph>
-  class GraphWriter;
-
-  template <typename Graph>
-  GraphWriter<Graph> graphWriter(const Graph& graph,
-                                 std::ostream& os = std::cout);
-
-  template <typename Graph>
-  GraphWriter<Graph> graphWriter(const Graph& graph, const std::string& fn);
-
-  template <typename Graph>
-  GraphWriter<Graph> graphWriter(const Graph& graph, const char *fn);
-
   /// \ingroup lemon_io
   ///
   /// \brief \ref lgf-format "LGF" writer for directed graphs
@@ -1526,37 +1535,6 @@
     /// @}
   };
 
-  /// \brief Return a \ref GraphWriter class
-  ///
-  /// This function just returns a \ref GraphWriter class.
-  /// \relates GraphWriter
-  template <typename Graph>
-  GraphWriter<Graph> graphWriter(const Graph& graph,
-                                 std::ostream& os = std::cout) {
-    GraphWriter<Graph> tmp(graph, os);
-    return tmp;
-  }
-
-  /// \brief Return a \ref GraphWriter class
-  ///
-  /// This function just returns a \ref GraphWriter class.
-  /// \relates GraphWriter
-  template <typename Graph>
-  GraphWriter<Graph> graphWriter(const Graph& graph, const std::string& fn) {
-    GraphWriter<Graph> tmp(graph, fn);
-    return tmp;
-  }
-
-  /// \brief Return a \ref GraphWriter class
-  ///
-  /// This function just returns a \ref GraphWriter class.
-  /// \relates GraphWriter
-  template <typename Graph>
-  GraphWriter<Graph> graphWriter(const Graph& graph, const char* fn) {
-    GraphWriter<Graph> tmp(graph, fn);
-    return tmp;
-  }
-
   class SectionWriter;
 
   SectionWriter sectionWriter(std::istream& is);