1. Aellig, M.R., Lazarus, A.J., Steinberg, J.T.: 2001, The solar wind helium abundance: Variation with wind speed and the solar cycle. Geophys. Res. Lett.
28, 2767 – 2770.
2. Baker, D.N., McPherron, R.L., Cayton, T.E., Klebesadel, R.W.: 1990, Linear prediction filter analysis of relativistic electron properties at 6.6 R
E. J. Geophys. Res.
95(A9), 15133 – 15140.
3. Chandra, S., Vats, H.O., Iyer, K.N.: 2009, Differential coronal rotation using radio images at 17 GHz. Mon. Not. Roy. Astron. Soc.
400, L34 – L37.
4. Cliver, E.W., Kamide, Y., Ling, A.G.: 2000, Mountains versus valleys: Semiannual variation of geomagnetic activity. J. Geophys. Res.
105, 2413 – 2424.
5. Emery, B.A., Evans, D.S., Greer, M.S., Kadinsky-Cade, K., Holeman, E., Rich, F.J., Xu, W.: 2005, NOAA and DMSP intersatellite adjusted hemispheric power data sets, described at
http://cedarweb.hao.ucar.edu/wiki/index.php/Instruments:ehp
in the Coupling, Energetics and Dynamics of Atmospheric Regions (CEDAR) Database at the National Center for Atmospheric Research (NCAR), Boulder, Colorado, USA (revised in 2007).