diff --git a/demo/binary_classification/README b/demo/binary_classification/README
index 64ef214df..86cd68992 100644
--- a/demo/binary_classification/README
+++ b/demo/binary_classification/README
@@ -9,3 +9,5 @@ Format of featmap.txt:
 
 q means continuous quantities, i means indicator features.
 Feature id must be from 0 to num_features, in sorted order.
+
+Detailed explaination: https://github.com/tqchen/xgboost/wiki/Binary-Classification