XENOS, T. D.; KOURIS, S. S.; ZOLESI, B. Assessment of the solar-cycle dependence of f0F2 1157. Annals of Geophysics, [S. l.], v. 39, n. 6, 1996. DOI: 10.4401/ag-4044. Disponível em: https://www.annalsofgeophysics.eu/index.php/annals/article/view/4044. Acesso em: 2 apr. 2026.