Elmunim, Nouf Abd, Mardina Abdullah, and Siti Aminah Bahari. “Characterization of Ionospheric Delay and Forecasting Using GPS-TEC over Equatorial Region”. Annals of Geophysics 63, no. 2 (May 26, 2020): PA211. Accessed October 27, 2021. https://www.annalsofgeophysics.eu/index.php/annals/article/view/8066.