update arxiv link

README.md

@@ -34,7 +34,7 @@ English | [简体中文]()
 
 <div align="center">
 
-[📜 Technical Report]() 
+[📜 Technical Report](https://arxiv.org/abs/2505.05427) 
 <!-- | [💻 Github Repo]() -->
 
 </div>
@@ -96,7 +96,14 @@ Thanks for their awesome work! Open-source contributions make Ultra-FineWeb poss
 If you find our work useful, please consider citing:
 
 ```bibtex
-Coming soon...
+@misc{wang2025ultrafineweb,
+  title={{Ultra-FineWeb}: Efficient Data Filtering and Verification for High-Quality LLM Training Data},
+  author={Yudong Wang and Zixuan Fu and Jie Cai and Peijun Tang and Hongya Lyu and Yewei Fang and Zhi Zheng and Jie Zhou and Guoyang Zeng and Chaojun Xiao and Xu Han and Zhiyuan Liu},
+  year={2025},
+  eprint={2505.05427},
+  archivePrefix={arXiv},
+  primaryClass={cs.CL},
+}
 ```
 
 ## 💳 License