MITCHELL, C. N.; SPENCER, P. S. J. A three-dimensional time-dependent algorithm for ionospheric imaging using GPS. Annals of Geophysics, [S. l.], v. 46, n. 4, p. 687–696, 2003. DOI: 10.4401/ag-4373. Disponível em: https://www.annalsofgeophysics.eu/index.php/annals/article/view/4373. Acesso em: 22 feb. 2024.