add references to README

README.md

@@ -89,4 +89,15 @@ Before training:
 ![t-SNE before](images/t-sne_without_training.png)
 
 After training:
-![t-SNE example](images/t-sne.png)
+![t-SNE example](images/t-sne.png)
+
+
+# References
+
+[1] Schroff, Florian, Dmitry Kalenichenko, and James Philbin. [Facenet: A unified embedding for face recognition and clustering.](https://arxiv.org/abs/1503.03832) CVPR 2015
+
+[2] Alexander Hermans, Lucas Beyer, Bastian Leibe, [In Defense of the Triplet Loss for Person Re-Identification](https://arxiv.org/pdf/1703.07737), 2017
+
+[3] Adam Bielski [Siamese and triplet networks with online pair/triplet mining in PyTorch](https://github.com/adambielski/siamese-triplet)
+
+[4] Olivier Moindrot [Triplet Loss and Online Triplet Mining in TensorFlow](https://omoindrot.github.io/triplet-loss)