Multimode LF and MF propagation in the Earth-ionosphere waveguide

Kirillov V.V., Kopejkin V.N., Shtennikov Yu.V. Multimode LF and MF propagation in the Earth-ionosphere waveguide // Изв. вузов. Радиофизика. 1993. Т. 36, № 2. C. 107–120.