Settimi, Alessandro, Umberto Sciacca, and Cesidio Bianchi. “Scientific Review on the Complex Eikonal, and Research Perspectives for the Ionospheric Ray-Tracing and Absorption”. Quaderni di Geofisica 112 (January 1, 2013). Accessed October 21, 2026. https://collane-editoriali.ingv.it/index.php/qdg/article/view/91.