diff -r 1af977819111 -r 9c23c3762bc5 doc/graph_io.dox
--- a/doc/graph_io.dox	Sat Oct 20 14:29:12 2007 +0000
+++ b/doc/graph_io.dox	Wed Oct 24 16:31:49 2007 +0000
@@ -335,7 +335,7 @@
 
 The specialization of writing is very similar to that of reading.
 
-\section u Undirected graphs
+\section undir Undirected and Bipartite graphs
 
 In a file describing an undirected graph (ugraph, for short) you find an
 \c uedgeset section instead of the \c edgeset section. The first line of
@@ -343,9 +343,9 @@
 next lines describe one undirected edge with the the incident nodes and the
 values of the map.
 
-The format handles directed edge maps as a syntactical sugar???, if there
-are two maps with names being the same with a \c '+' and a \c '-' prefix
-then this will be read as a directed map.
+The format could store directed edge maps, if there are two maps with 
+names being the same with a \c '+' and a \c '-' prefix then this could 
+be read as such a map.
 
 \code
 @uedgeset
@@ -386,6 +386,35 @@
 reader.readEdge("edge", edge);
 \endcode
 
+The undirected bipartite graphs could be read with the \c BpUGraph
+class and it has specialized nodeset section, which should be start
+with \c "@bpnodeset". This section is separated to two
+subsections. The header line of these sections start with "&anodeset"
+or "&bnodeset" and after that the line contains the names of the
+regular and A-node or B-node maps accordingly. The lines of each
+section contains the mapped values. The labels of the graph should be
+unique overall both subsections.
+
+\code
+@bpnodeset
+&anodeset label   coords	radius
+	  0       (0, 0)	14.0
+	  1       (0, 1)	12.0
+&bnodeset label	  coords
+	  2       (1, 0)
+	  3       (1, 1)
+\endcode
+
+The reading can be done with \ref lemon::BpUGraphReader::readANodeMap() 
+"readANodeMap()", \ref lemon::BpUGraphReader::readBNodeMap() 
+"readBNodeMap()" or \ref lemon::BpUGraphReader::readNodeMap() 
+"readNodeMap()" members.
+
+\code
+reader.readNodeMap("coords", coords);
+reader.readAnodeMap("radius", radius);
+\endcode
+
 \section advanced Advanced features
 
 The graph reader and writer classes give an easy way to read and write