Update citation with bioRxiv preprint

README.md

@@ -17,4 +17,16 @@ This repository uses a custom license. See the [LICENSE](LICENSE.md) file for fu
 
 ## Citations
 
-TBD
+Please cite our paper:
+
+```bibtex
+@article{li2026direct,
+  title        = {Direct Detection and Atomic Modeling of Ligands in Cryo-EM Maps Using Deep Learning},
+  author       = {Li, Shu and Jain, Anika and Kagaya, Yuki and Park, Joon Hong and Kihara, Daisuke},
+  journal      = {bioRxiv},
+  year         = {2026},
+  doi          = {10.64898/2026.06.01.729423},
+  url          = {https://www.biorxiv.org/content/10.64898/2026.06.01.729423v1},
+  note         = {Preprint}
+}
+```