SETTIMI, Alessandro. Ray theory formulation and ray tracing method. Application in ionospheric propagation. Quaderni di Geofisica, [S. l.], v. 121, 2014. DOI: 10.13127/qdg/121. Disponível em: https://collane-editoriali.ingv.it/index.php/qdg/article/view/100. Acesso em: 20 ott. 2026.