GUALTIERI, G.; MURRI, A. The vertical gradient of Electro-Atmospheric potential at Macerata (Italy) (Central East Apennines). Annals of Geophysics, [S. l.], v. 22, n. 1, p. 33–55, 1969. DOI: 10.4401/ag-5080. Disponível em: https://www.annalsofgeophysics.eu/index.php/annals/article/view/5080. Acesso em: 20 sep. 2021.