Update DB-2021.md

Author: heathersherry

topics/DB-2021.md

@@ -35,7 +35,7 @@ Short papers or Demos：
 2. A Survey on Data Collection for Machine Learning: A Big Data - AI Integration Perspective [[Paper](https://ieeexplore.ieee.org/document/8862913/)]
 3. An Embedding-Based Approach to Rule Learning in Knowledge Graphs [[Paper](https://ieeexplore.ieee.org/document/8839576/)]
 4. Neural Named Entity Boundary Detection [[Paper](https://ieeexplore.ieee.org/document/9039695/)]
-5. Learning Dynamic User Interest Sequence in Knowledge Graphs for Click-Through Rate Prediction
+5. Learning Dynamic User Interest Sequence in Knowledge Graphs for Click-Through Rate Prediction [[Paper](https://ieeexplore.ieee.org/document/9409651)]
 
 Some interesting papers:
 1. Duration Modeling with Semi-Markov Conditional Random Fields for Keyphrase Extraction