add paper link

Author: ZhiYeG

README.md

@@ -164,4 +164,4 @@ H1017A_H1017B   110   125   60.0000    60.0000    54.5455    50.0000    41.8182
 This project is covered under the **MIT License**.
 
 ## Reference
-Z. Guo, J. Liu, J. Skolnick, J. Cheng. Prediction of inter-chain distance maps of protein complexes with 2D attention-based deep neural networks. Submited.
+[Guo, Z., Liu, J., Skolnick, J., & Cheng, J. (2022). Prediction of inter-chain distance maps of protein complexes with 2D attention-based deep neural networks. bioRxiv.](https://www.biorxiv.org/content/10.1101/2022.06.19.496734v1)