The multi-spacecraft high-energy solar particle event of 28 October 2021 A. Kouloumvakos, A. Papaioannou, C. O. G. Waterfall, S. Dalla, R. Vainio, G. M. Mason, B. Heber, P. Kühl, R. C. Allen, C. M. S. Cohen et al. (8 more) A&A, 682 (2024) A106 Published online: 09 February 2024 DOI: 10.1051/0004-6361/202346045