Update README.md

README.md

@@ -148,6 +148,6 @@ After a few epochs, the attention layer converges perfectly to what we expected.
 
 ## References
 
-- https://www.cs.cmu.edu/~./hovy/papers/16HLT-hierarchical-attention-networks.pdf
-- https://arxiv.org/abs/1508.04025
-- https://arxiv.org/abs/1409.0473
+- [Hierarchical Attention Networks for Document Classification](https://www.cs.cmu.edu/~./hovy/papers/16HLT-hierarchical-attention-networks.pdf)
+- [Effective Approaches to Attention-based Neural Machine Translation](https://arxiv.org/abs/1508.04025)
+- [Neural Machine Translation by Jointly Learning to Align and Translate](https://arxiv.org/abs/1409.0473)