Edit README.md

README.md

@@ -24,6 +24,7 @@
   * [Validity ranges](#validity-ranges)
 * [License](#license)
 * [Contact](#contact)
+* [How to cite this work](#cite)
 * [Acknowledgements](#acknowledgements)
 
 
@@ -98,7 +99,13 @@ Due to biases at the boundary of the RMF modeling, induced by features in the in
 Valentina Fioretti (INAF OAS Bologna) - valentina.fioretti<at>inaf.it
 Project Link: [https://ahead.iaps.inaf.it/](https://ahead.iaps.inaf.it/)
 
+<!-- CITE -->
+## How to cite this work
 
+Please make sure to cite the following papers if you use the proton response files:
+
+- [V. Fioretti et al., "Unveiling the origin of XMM-Newton soft proton flares I. Design and validation of a response matrix for proton spectral analysis", A&A, 691, A229 (2024)](https://www.aanda.org/articles/aa/full_html/2024/11/aa51231-24/aa51231-24.html)
+- [T. Mineo et al., "Unveiling the origin of XMM-Newton soft proton flares II. Systematics in the proton spectral analysis", A&A, 691, A230 (2024)](https://www.aanda.org/articles/aa/full_html/2024/11/aa51232-24/aa51232-24.html)
 
 <!-- ACKNOWLEDGEMENTS -->
 ## Acknowledgements