Bianchi, C., and A. Meloni. “Natural and Man-Made Terrestrial Electromagnetic Noise: An Outlook”. Annals of Geophysics 50, no. 3 (December 25, 2007): 435–445. Accessed April 26, 2024. https://www.annalsofgeophysics.eu/index.php/annals/article/view/4425.