Update README.md

README.md

@@ -69,5 +69,10 @@ image.save('moon.png')
 ## Citation
 If you find our work or codebase useful, please consider giving us a star and citing our work.
 ```
-
+@article{liang2024step,
+  title={Step-aware Preference Optimization: Aligning Preference with Denoising Performance at Each Step},
+  author={Liang, Zhanhao and Yuan, Yuhui and Gu, Shuyang and Chen, Bohan and Hang, Tiankai and Li, Ji and Zheng, Liang},
+  journal={arXiv preprint arXiv:2406.04314},
+  year={2024}
+}
 ```