BRADLEY, P. A. International activities in HF sky-wave field-strength estimation (period 1956-1991). Annals of Geophysics, [S. l.], v. 41, n. 5-6, 1998. DOI: 10.4401/ag-3811. Disponível em: https://www.annalsofgeophysics.eu/index.php/annals/article/view/3811. Acesso em: 1 oct. 2022.