Update README.md

Author: Nativeatom

Embedding/README.md

@@ -6,6 +6,8 @@
 
 ### Word2Vec
 * Overview by Xin Rong *[word2vec Parameter Learning Explained](https://arxiv.org/pdf/1411.2738.pdf)* [[Video] (https://www.youtube.com/watch?v=D-ekE-Wlcds)]
+* Explanation of Negative Sampling *[word2vec Explained:  Deriving Mikolov et al.’s Negative-Sampling Word-Embedding Method](https://arxiv.org/pdf/1402.3722.pdf)*
+* Connection of Negative Sampling and Mutual Information *[Neural Word Embedding as Implicit Matrix Factorization](https://pdfs.semanticscholar.org/e0d7/69c5698275c2f745c1aac2aebc323f51aa24.pdf?_ga=2.100986117.540785117.1516862569-662515382.1516862569)* 14'
 
 #### Variant
 * emoji2vec