@article{DAN_1961_139_1_a17,
     author = {P. E. Krasnushkin},
     title = {The propagation of long and ultra-long radio waves about the earth in the lower ($C$, $D$, and $E$) layers 
},
     journal = {Doklady Akademii Nauk},
     pages = {67--70},
     publisher = {mathdoc},
     volume = {139},
     number = {1},
     year = {1961},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1961_139_1_a17/}
}