@inproceedings{Cliver:2023q5, author = "Cliver, Edward", title = "{Extreme Solar Energetic Proton Events}", doi = "10.22323/1.423.0004", booktitle = "Proceedings of 27th European Cosmic Ray Symposium {\textemdash} PoS(ECRS)", year = 2023, volume = "423", pages = "004" }