DEL CASTILLO, José. SECTION 1: Static or Frictional Electricity and the Discovery of Direct Current. Puerto Rico Health Sciences Journal, [S. l.], v. 16, n. 4, 2019. Disponível em: https://prhsj.rcm.upr.edu/index.php/prhsj/article/view/2168. Acesso em: 19 dec. 2025.