1. Sporadic-E at VHF in the USA;Davis;Proc. IRE,1959
2. Sporadic-E propagation;Gerson;J. Atmosphere Terrest. Phys.,1955
3. Estimation of the strength of Es waves by f0Es at the midpoint;Kobayashi;J. Radio Res. Labs. (Tokyo),1964
4. Study of long distance propagation of VHF waves by sporadic-E ionization;Kono;J. Radio Res. Labs. (Tokyo),1954