Update README.md

Author: jind11

README.md

@@ -1,7 +1,16 @@
 # TextFooler
 A Model for Natural Language Attack on Text Classification and Inference
 
-This is the source code for the paper: [Jin, Di, et al. "Is BERT Really Robust? Natural Language Attack on Text Classification and Entailment." arXiv preprint arXiv:1907.11932 (2019)](https://arxiv.org/pdf/1907.11932.pdf).
+This is the source code for the paper: [Jin, Di, et al. "Is BERT Really Robust? Natural Language Attack on Text Classification and Entailment." arXiv preprint arXiv:1907.11932 (2019)](https://arxiv.org/pdf/1907.11932.pdf). If you use the code, please cite the paper:
+
+```
+@article{jin2019bert,
+  title={Is bert really robust? natural language attack on text classification and entailment},
+  author={Jin, Di and Jin, Zhijing and Zhou, Joey Tianyi and Szolovits, Peter},
+  journal={arXiv preprint arXiv:1907.11932},
+  year={2019}
+}
+```
 
 ## Prerequisites:
 * Pytorch >= 0.4