1. Effect on the lower ionosphere of X-rays from Scorpius XR-1;Anathakrishnan;Nature, Lond.,1969
2. Gq, a Galactic component of the geomagnetic field variation.;Campbell;Radio Sci.,1971
3. Geomagnetism;Chapman,1940
4. Atmospheric Tides;Chapman,1970
5. Very low frequency observations of nightghtime D-region ionization enhancements by Scorpius XR-1 X-ray source;Chilton,1970