Sumaruk, Yu. P., and T. Sumaruk. “Features of Age Variations of the Geomagnetic Field in the Northern Polar Part of the Earth”. Geofizicheskiy Zhurnal 35, no. 2 (March 1, 2013): 137–145. Accessed April 24, 2024. https://journals.uran.ua/geofizicheskiy/article/view/111357.