Update README.md

Author: cryptopathe

README.md

@@ -1,3 +1,18 @@
 Please have a look at the [wiki](https://github.com/obfuscator-llvm/obfuscator/wiki) !
 
 Current version: [LLVM-3.5.0](https://github.com/obfuscator-llvm/obfuscator/tree/llvm-3.5)
+
+You can cite Obfuscator-LLVM using the following Bibtex entry:
+
+```
+@INPROCEEDINGS{ieeespro2015-JunodRWM,
+  author={Pascal Junod and Julien Rinaldini and Johan Wehrli and Julie Michielin},
+  booktitle={Proceedings of the {IEEE/ACM} 1st International Workshop on Software Protection, {SPRO'15}, Firenze, Italy, May 19th, 2015},
+  editor = {Brecht Wyseur},
+  publisher = {IEEE},
+  title={Obfuscator-{LLVM} -- Software Protection for the Masses},
+  year={2015},
+  pages={3--9},
+  doi={10.1109/SPRO.2015.10},
+}
+```