A. Būga, S. Einorytė, R. Obuchovski, V. Puškorius, and P. Petroškevičius, “Analysis of secular variations of geomagnetic field in Lithuania based on the survey in 2016”, ENVIRO, vol. 10, pp. 1–6, Jan. 2017, doi: 10.3846/enviro.2017.170.