Update README.md

add bibtex

README.md

@@ -90,6 +90,20 @@ Please refer to [MODEL_ZOO.md](docs/MODEL_ZOO.md) for for a comprehensive set of
 
 This project is released under the [Apache 2.0 license](LICENSE).
 
+## Citation
+
+If you use this toolbox in your research, please consider cite:
+
+```
+@inproceedings{zhan2020online,
+  title={Online Deep Clustering for Unsupervised Representation Learning},
+  author={Zhan, Xiaohang and Xie, Jiahao and Liu, Ziwei and Ong, Yew-Soon and Loy, Chen Change},
+  booktitle={Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition},
+  pages={6688--6697},
+  year={2020}
+}
+```
+
 ## Acknowledgement
 
 - This repo borrows the architecture design and part of the code from [MMDetection](https://github.com/open-mmlab/mmdetection).