Update README.md

policy/feudalgainRL/README.md

@@ -2,7 +2,7 @@
 
 This is the implementation to the work **What Does The User Want? Information Gain for Hierarchical Dialogue Policy Optimisation**, published at ASRU2021.
 
-Reference: 
+Reference: https://arxiv.org/pdf/2109.07129.pdf
 
 #### Train a FeudalGain policy
 
@@ -44,4 +44,4 @@ js_threshold = 1.0
 architecture = duel
 ```
 
-Log files and policies will be saved in the directories specified in the config file in section **[exec_config]**.
\ No newline at end of file
+Log files and policies will be saved in the directories specified in the config file in section **[exec_config]**.