fix reference

doc/library/tensor/nnet/bn.txt

@@ -10,7 +10,6 @@
 .. moduleauthor:: LISA
 
 
-.. seealso:: :ref:`cuDNN batch normalization <libdoc_cuda_dnn_bn>`
-    must be added manually.
+.. seealso:: cuDNN batch normalization: :class:`theano.gpuarray.dnn.dnn_batch_normalization_train`, :class:`theano.gpuarray.dnn.dnn_batch_normalization_test>`. They must be added manually as they do not have the same user interface.
 
 .. autofunction:: theano.tensor.nnet.bn.batch_normalization