Update README.md

README.md

@@ -59,6 +59,12 @@ $ python3 absinth.py -t
 * [Spacy](https://spacy.io/) - Tokenisation and syntactic parsing
 * [NumPy](http://www.numpy.org/) - Maths
 
+## References
+
+Di Marco, Antonio and Navigli, Roberto (2013). Clustering and Diversifying Web Search Results with Graph-Based Word Sense Induction. Computational Linguistics, 39(3). doi:10.1162/COLI_a_00148
+Kruskal, J. (1956). On the Shortest Spanning Subtree of a Graph and the Traveling Salesman Problem. Proceedings of the American Mathematical Society, 7(1), 48-50. doi:10.2307/2033241
+Véronis, Jean. (2004). HyperLex: Lexical cartography for information retrieval. Computer Speech & Language. doi:10.1016/j.csl.2004.05.002
+
 ## Authors
 
 * **Maja Hoffmann** - [hoffmann](https://gitlab.cl.uni-heidelberg.de/hoffmann/)