GULYAEVA, T. L.; STANISLAWSKA, I. Regional study of the ionosphere quietness over Europe. Annals of Geophysics, [S. l.], v. 37, n. 1, 1994. DOI: 10.4401/ag-4238. Disponível em: https://www.annalsofgeophysics.eu/index.php/annals/article/view/4238. Acesso em: 27 nov. 2021.