Update README.md

README.md

@@ -1405,6 +1405,6 @@ GreekMMLU includes 45 subjects, grouped into:
 See the paper for the full taxonomy and educational-level breakdown.
 
 ## Citation
-If you use GreekMMLU in your work, please cite the paper:
+If you use GreekMMLU in your work, please cite the paper: https://www.arxiv.org/abs/2602.05150