Update README.md

Author: dou-du

README.md

@@ -53,6 +53,16 @@ The `screenshot comparison` test will generate images of the widget using `selen
 
 To update the reference image: download the generated image from the Github Workflow step called "Upload screenshots".
 
+## How to cite
+
+When using the content of this repository, please cite the following two articles:
+
+1. D. Du, T. J. Baird, S. Bonella and G. Pizzi, OSSCAR, an open platform for collaborative development of computational tools for education in science, *Computer Physics Communications*, **282**, 108546 (2023).
+https://doi.org/10.1016/j.cpc.2022.108546
+
+2. D. Du, T. J. Baird, K. Eimre, S. Bonella, G. Pizzi, Jupyter widgets and extensions for education and research in computational physics and chemistry, *Computer Physics Communications*, **305**, 109353 (2024).
+https://doi.org/10.1016/j.cpc.2024.109353
+
 ## Acknowledgements
 
 We acknowledge support from the EPFL Open Science Fund via the [OSSCAR](http://www.osscar.org) project.