diff --git a/README.md b/README.md
index a49814f..33a9f8c 100644
--- a/README.md
+++ b/README.md
@@ -3,7 +3,7 @@ sentence2vec
 
 Tools for mapping a sentence with arbitrary length to vector space
 
-We provide an implementation of the Paragraph Vector in Quoc Le and Tomas Mikolov's paper: Distributed representations of Sentences and Documents.
+We provide an implementation of the Paragraph Vector in Quoc Le and Tomas Mikolov's paper: [Distributed representations of Sentences and Documents][2].
 
 This project is based on [gensim][1].
 
@@ -13,6 +13,7 @@ install requires:
  - 'six >= 1.2.0'
 
   [1]: https://github.com/piskvorky/gensim
+  [2]: http://arxiv.org/abs/1405.4053
 
 
 2014-9-23 update: add test files for demo.