1.1 --- a/lgf.dox	Mon Mar 01 02:27:36 2010 +0100
     1.2 +++ b/lgf.dox	Mon Mar 01 02:28:05 2010 +0100
     1.3 @@ -109,14 +109,31 @@
     1.4      .attribute("caption", title)
     1.5      .run();
     1.6  \endcode
     1.7 +
     1.8 +Undirected graphs can be stored in LGF format in almost the same way.
     1.9 +The <tt>\@arcs</tt> section can also be called <tt>\@edges</tt>, they are
    1.10 +identical. The only speciality is that arc maps can be distinguished from
    1.11 +edge maps using a \c + or \c - prefix before the name of the map.
    1.12 +For example,
    1.13 +
    1.14 +\code
    1.15 +  @edges
    1.16 +            label  +length  -length  
    1.17 +  0    1    0      10       20
    1.18 +  ...
    1.19 +\endcode
    1.20 +
    1.21 +In conjunction with undirected graphs, the classes \ref GraphReader and
    1.22 +\ref GraphWriter can be used.
    1.23   
    1.24 -Apart from LGF, the library can also handle other graph
    1.25 +For more information, see the \ref lgf-format "description of the LGF format"
    1.26 +and the \ref io_group module in the reference manual.
    1.27 +For a working example, see \ref lgf_demo.cc in the demo directory
    1.28 +of the LEMON source.
    1.29 +
    1.30 +\note Apart from LGF, the library can also handle other graph
    1.31  formats, such as the well-known DIMACS format.
    1.32  
    1.33 -For more information, see a more detailed \ref lgf-format
    1.34 -"description of the LGF format" and the \ref io_group module
    1.35 -in the reference manual.
    1.36 -
    1.37  [TRAILER]
    1.38  */
    1.39  }