diff --git a/docs/References.rst b/docs/References.rst
index 259b0a2..221becf 100644
--- a/docs/References.rst
+++ b/docs/References.rst
@@ -5,6 +5,25 @@ Zhi-Hua Zhou. `Abductive learning: Towards bridging machine learning and logical
 
 Zhi-Hua Zhou and Yu-Xuan Huang. `Abductive learning <https://www.lamda.nju.edu.cn/publication/chap_ABL.pdf>`_. In P. Hitzler and M. K. Sarker eds., **Neuro-Symbolic Artificial Intelligence: The State of the Art**, IOP Press, Amsterdam, 2022, p.353-379
 
+.. code-block:: latex
 
+    @article{zhou2019abductive,
+        title     = {Abductive learning: towards bridging machine learning and logical reasoning},
+        author    = {Zhou, Zhi-Hua},
+        journal   = {Science China Information Sciences},
+        volume    = {62},
+        number    = {7},
+        pages     = {76101},
+        year      = {2019}
+    }
 
-
+    @incollection{zhou2022abductive,
+        title     = {Abductive Learning},
+        author    = {Zhou, Zhi-Hua and Huang, Yu-Xuan},
+        booktitle = {Neuro-Symbolic Artificial Intelligence: The State of the Art},
+        editor    = {Pascal Hitzler and Md. Kamruzzaman Sarker},
+        publisher = {{IOS} Press},
+        pages     = {353--369},
+        address   = {Amsterdam},
+        year      = {2022}
+    }