Update README.md

README.md

@@ -90,7 +90,12 @@ print(output_text[0])
 ## Citation
 
 ```bibtex
-TBD
+@article{piao2026safeguardvl,
+  title={Towards Policy-Adaptive Image Guardrail: Benchmark and Method},
+  author={Piao, Caiyong Piao and Yan, Zhiyuan and Xu, Haoming and Zhao, Yunzhen and Lin, Kaiqing and Xu, Feiyang and Zhou, Shuigeng},
+  journal={arXiv preprint arXiv:2603.01228},
+  year={2026}
+}
 ```
 
 ## Disclaimer