Add citation

README.md

@@ -93,4 +93,17 @@ SwissBERT is not designed for generating text.
 - Site: Zurich, Switzerland.
 - Energy source: 100% hydropower ([source](https://t.uzh.ch/1rU))
 - Carbon efficiency: 0.0016 kg CO2e/kWh ([source](https://t.uzh.ch/1rU))
-- Carbon emitted: 0.6 kg CO2e ([source](https://mlco2.github.io/impact#compute))
+- Carbon emitted: 0.6 kg CO2e ([source](https://mlco2.github.io/impact#compute))
+
+## Citation
+```bibtex
+@article{vamvas-etal-2023-swissbert,
+      title={Swiss{BERT}: The Multilingual Language Model for Switzerland}, 
+      author={Jannis Vamvas and Johannes Gra\"en and Rico Sennrich},
+      year={2023},
+      eprint={2303.13310},
+      archivePrefix={arXiv},
+      primaryClass={cs.CL},
+      url={https://arxiv.org/abs/2303.13310}
+}
+```