RAO , K. S. R. ., and A. T. . THOMAS. “Lunar and Solar Geomagnetic Tides in the Geomagnetic Equatorial Region- III Geomagnetic Tidal Variations at Apia”. MAUSAM, vol. 13, no. 2, Apr. 1962, pp. 237-40, doi:10.54302/mausam.v13i2.4355.