Update README.md

README.md

@@ -30,7 +30,7 @@ If you find this project helpful for your research or use it in your own work, p
       author       = {Zigang Geng, Yibing Wang, Yeyao Ma, Chen Li, Yongming Rao, Shuyang Gu, Zhao Zhong, Qinglin Lu, Han Hu, Xiaosong Zhang, Linus, Di Wang and Jie Jiang},
       title        = {X-Omni: Reinforcement Learning Makes Discrete Autoregressive Image Generative Models Great Again},
       journal      = {CoRR},
-      volume       = {abs/None},
+      volume       = {abs/2507.22058},
       year         = {2025},
 }
 ```