AEC research reports. AEC-tr-3493. Propagation of electro-magnetic waves in plasma (ionosphere) (Rasprostranenie elektromagnitnykh voln v plazme (ionosfere) [with list of literature cited]; by B. N. Gershman, V. L. Ginsburg, N. G. Denisov; translated from Uspekhi Fiz. Nauk 61, 561-612 (1957), by David Franklin.