1. Ionospheric absorption at vertical and oblique incidence;Allcock,1954
2. Regularities and irregularities in the ionosphere-I;Appleton,1937
3. Ionospheric absorption measurements throughout a sunspot cycle;Appleton,1948
4. Ionospheric absorption measurements during a sunspot cycle;Appleton;J. Atmos. Terr. Phys.,1954
5. A study of vertical incidence ionospheric absorption at 2 mc/s;Beynon,1954