diff --git a/README.md b/README.md
index 7a45ce0c8..f2c517ec8 100644
--- a/README.md
+++ b/README.md
@@ -119,3 +119,15 @@ cs.__citation__
 ```
 
 **We have no original papers the author and contributors wrote, but note that some scientific approaches, including SIR-F model, S-R change point analysis, phase-dependent approach to SIR-derived models, were developed in this project.**
+
+BibTeX format citation is here.
+
+```
+@misc{covsirphy_repo,
+author = {Hirokazu Takaya and CovsirPhy Development Team},
+title = {CovsirPhy version [version number]: Python library for COVID-19 analysis with phase-dependent SIR-derived ODE models},
+year = {2020},
+url = {https://github.com/lisphilar/covid19-sir},
+note = {Accessed: YYYY-MM-DD}
+}
+```
diff --git a/data/README.md b/data/README.md
index 8874943e0..d8fb427e2 100644
--- a/data/README.md
+++ b/data/README.md
@@ -146,3 +146,15 @@ Kindly cite this dataset under CC BY-4.0 license as follows.
 
 - Hirokazu Takaya (2020-2023), COVID-19 dataset in Japan, GitHub repository, <https://github.com/lisphilar/covid19-sir/data/japan>, or
 - Hirokazu Takaya (2020-2023), COVID-19 dataset in Japan, Kaggle Dataset, <https://www.kaggle.com/lisphilar/covid19-dataset-in-japan>
+
+BibTeX format citation is here.
+
+```
+@misc{covid19_jp_repo,
+author = {Hirokazu Takaya},
+title = {COVID-19 dataset in Japan},
+year = {2020},
+url = {https://github.com/lisphilar/covid19-sir/data/japan},
+note = {Accessed: YYYY-MM-DD}
+}
+```