Add citation

README.md

@@ -123,3 +123,15 @@ python train.py \
     --fp16 \
     --seed 28852
 ```
+
+## Citation
+```bibtex
+@article{vamvas-sennrich-2023-rsd,
+      title={Towards Unsupervised Recognition of Semantic Differences in Related Documents},
+      author={Jannis Vamvas and Rico Sennrich},
+      year={2023},
+      eprint={2305.13303},
+      archivePrefix={arXiv},
+      primaryClass={cs.CL}
+}
+```