Update README.md

Add publication.

README.md

@@ -76,3 +76,15 @@ check is performed when each middle routers receive a package. In case of a mism
 the routing monitor invokes the wrong routing path error. This component ensures that
 the routing path of the packets is maintained throughout the verification process.
 
+## Publication
+
+If you use OpenExSys in your work, you can cite us:
+
+```
+@inproceedings{fu2023cache,
+  title={Cache Coherent Framework for RISC-V Many-core Systems},
+  author={Fu, Zexin and Wang, Mingzi and Zhang, Yihai and Tan, Zhangxi},
+  booktitle={Seventh Workshop on Computer Architecture Research with RISC-V (CARRV)},
+  year={2023}
+}
+```