REFERENCES
- Watt(A D). VLF Radio Engineering. Pergamon Press Inc., Oxford, England. 1967.
- Swanson (ER). Navigation. 18, 2; 1971: 168–175.
- Blair (B E). Time and Frequency: Theory and Fundamentals. NBS Monograph 140, 1974. P 241–244.
- Belrose (J S). AGARD “Radio wave propagation”, AGARD Lecture series XXIX, July, 1968.
- Belrose (J S). (Chairman), CCIR Report 265–4, 1978.
- Sen Gupta (A), Goel (G K) & Mathur (B S), Paper Presented at the XII Ann. PTTI Meeting, Washington, Dec. 2–4, 1980.
- Becker (G), Fisher (B) & Kramer (G). Proc. Colloque International de Chronometrie, Paris, France, 1969.
- Fey (R L) & Looney (CH). IEEE Trans. IM-15, 4; 1966; 190–195.
- Budden (G K). The Waveguide Mode Theory of Wave Propagation. 1961. Logos Press Ltd., London.
- Wait (J R) & Spies (K P). NBS Tech. Note. 300, 1964.
- Reder (FH). Progress in Radio Science: 1966; 1969; 2, URSI, Belgium, 1971.
- Lynn (K J W). Journ. Atoms. Terr. Phys. 33, 1971; 951.
- Lynn (K J W). Journ. Atmos. Terr. Phys. 39, 1977; 347.
- Swanson (E R) & Bradford (W R). NELC (USA), Tech. Rep. 1781. Aug. 1971.
- lijima (S), Torao (M) & Fujiwara (K). Annals of Tokyo Astron. Observ. 2nd Series, 11, p, 1968.
- Burgess (B) & Jones (T B). Radio Science. 2. 1967; 619.
- Mitra (A P) & Deshpande (S D). Journ. Atmos. Terr. Phys. 1971.
- Westerlund(S), Reder (FH) & Abom (C). Planet Space Science. 17, 1969; 1329–1374.