VALACH F, VÁCZYOVÁ M, VÝBERČI D, KOČI E. Regular observations of the geomagnetic field at the Ógyalla observatory (present-day Hurbanovo) near the turn of the 20th century, including magnetic storms accompanied by auroras in March 1894, September 1898, and October 1903. Contrib. Geophys. Geod. [Internet]. 2024Apr.1 [cited 2024Nov.23];54(1):23-8. Available from: https://journal.geo.sav.sk/cgg/article/view/497