diff --git a/ref.bib b/ref.bib
index 784f2d68de69720890cf787501ad566c773d1099..7d880828167b6b293139122d2d7a33014f196d78 100644
--- a/ref.bib
+++ b/ref.bib
@@ -25,3 +25,8 @@
   year={2014},
   organization={ACM}
 }
+@article{kille2015overview,
+  title={Overview of CLEF NewsREEL 2015: News Recommendation Evaluation Lab},
+  author={Kille, Benjamin and Lommatzsch, Andreas and Turrin, Roberto and Ser{\'e}ny, Andr{\'a}s and Larson, Martha and Brodt, Torben and Seiler, Jonas and Hopfgartner, Frank},
+  year={2015}
+}