Stamper, R., J. Lilensten, and N. Jakowski. “Nowcasting, Forecasting and Warning for Ionospheric Propagation: Supporting Databases”. Annals of Geophysics 47, no. 2-3 Sup. (December 25, 2004). Accessed April 20, 2024. https://www.annalsofgeophysics.eu/index.php/annals/article/view/3280.