VELINOV, P. Major X-Class Solar Flare from Earth-Facing Active Region AR12887 on October 28, 2021 and First Cosmic Ray GLE 73 in Solar Cycle 25. Proceedings of the Bulgarian Academy of Sciences, Sofia, Bulgaria, v. 75, n. 2, p. 248–258, 2022. DOI: 10.7546/CRABS.2022.02.10. Disponível em: https://www.proceedings.bas.bg/index.php/cr/article/view/29. Acesso em: 22 oct. 2026.