Telecommunications research and engineering report OT/TRER (series). 13. Ionospheric predictions: v. 3, Maximum usable frequencies MUF(ZERO)F2, MUF(4000)F2 and MUF(20OO)E for maximum solar activity period of average solar cycle R12=10O; [by] William M. Roberts [and] Rayner K. Rosich.

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