Não informado. (1944). Ionospheric data. U.S. Department of Commerce, National Bureau of Standards, Central Radio Propagation Laboratory.
Chicago-referens (17:e uppl.)Não informado. Ionospheric Data. Washington: U.S. Department of Commerce, National Bureau of Standards, Central Radio Propagation Laboratory, 1944.
MLA-referens (8:e uppl.)Não informado. Ionospheric Data. U.S. Department of Commerce, National Bureau of Standards, Central Radio Propagation Laboratory, 1944.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.