Warrington, E. M., Stocker, A. J., Zaalov, N. Y., Siddle, D. R., & Nasyrov, I. A. (2004). Propagation of HF radio waves over northerly paths: measurements,simulation and systems aspects. Annals of Geophysics, 47(2-3 Sup.). https://doi.org/10.4401/ag-3292