1. Time relationship of small magnetic disturbances in Arctic and Antarctic;Ahmed;J. Geophys. Res.,1955
2. Persistent disturbance in the polar regions on geomagnetically quiet days (abstract);Fukushima;J. Geophys. Res.,1961
3. Polar magnetic storms, especially in the southern polar region;Nagata;J. Phys. Soc. Japan,1962
4. Constitution of polar magnetic storms;Nagata;Rep. Ionosphere Res., Japan,1952
5. Polar magnetic storms, vlith special reference to relations between geomagnetic disturbances in the northern and southern auroral zones;Nagata;Rep. Ionosphere and Space Res., Japan,1960