• Barghausen, A. F., J. W. Finney, L. L. Proctor, L. D. Shultz, Predicting long-term operational parameters of high-frequency skywave telecommunication systemsESSA Tech. Rep. ERL 110-ITS78U.S. Dep. of Commer., Washington, D.C., 1969.
  • Caruana, J., The IPS monthly T index, Solar-Terrestrial Predictions: Proceedings of a Workshop at Leura, Australia, 1R. J. Thompson, et al., 257263, U.S. Dep. of Commer., Boulder, Colo., 1989.
  • , CCIR, CCIR atlas of ionospheric characteristicsRep. 340Int. Telecommun. Union, Geneva, 1967.
  • , CCIR, CCIR atlas of ionospheric characteristics (supplement)Rep. 343Int. Telecommun. Union, Geneva, 1978.
  • Flattery, T. W., A. C. Ramsay, Derivation of total electron content for real time global applications, Effect of the Ionosphere on Space Systems and CommunicationsJ. Goodman, 336344, Nat. Tech. Info. Serv., Springfield, Va., 1975.
  • Hart, M. L., Effective sunspot number (SSN1) comparison studyUSAFETAC/PR-90/05USAF Environ. Tech. Appl. Cent., Scott Air Force Base, Ill., 1990.
  • Jones, W. B., D. L. Obitts, Global representation of annual and solar cycle variation of ƒoF2 monthly median 1954–1958Telecommun. Res. Rep. OT/ITSRR3Off. of Telecommun., U.S. Dep. of Commer., Boulder, Colo., 1970.
  • Liu, R. Y., P. A. Smith, J. W. King, A new solar index which leads to improved ƒoF2 predictions using the CCIR atlas, Telecommun. J., 50, 408414, 1983.
  • Minnis, C. M., A new index of solar activity based on ionospheric measurements, J. Atmos. Terr. Phys., 7, 310321, 1955.
  • Minnis, C. M., G. H. Bazzard, A monthly ionospheric index of solar activity based on F2-layer ionization at eleven stations, J. Atmos. Terr. Phys., 18, 297305, 1960.
  • Rush, C. M., M. Fox, D. Bilitza, K. Davies, L. McNamara, F. Stewart, M. PoKempner, Ionospheric mapping: An update of ƒoF2 coefficients, Telecommun. J., 56, 179182, 1989.
  • Stewart, F. G., M. Leftin, Relationship between Ottawa 10.7 cm solar radio noise flux and Zurich sunspot number, Telecommun. J., 39, 159169, 1972.
  • Turner, J. F., The development of the ionospheric index T, IPS Ser. RRep. R11Ionos. Predict. Serv., West Chatswood, N.S.W., AustraliaJune, 1968.
  • vonFlotow, C. S., Ionospheric forecasting at Air Force Global Weather Central, Effect of the Ionosphere on Space and Terrestrial SystemsJ. Goodman, 385392, U.S. Govt. Print. Off., Washington, D. C., 1978.
  • Wilkinson, P. J., Predictability of ionospheric variations for quiet and disturbed conditions, J. Atmos. Terr. Phys., 57, 14691481, 1995.