CHEN, Junhong. Approximate Methods for Calculating Ground-State Energy in Helium Atom. Highlights in Science, Engineering and Technology, [S. l.], v. 141, p. 59–65, 2025. DOI: 10.54097/y8y88h27. Disponível em: https://hsetdata.com/index.php/ojs/article/view/647. Acesso em: 13 may. 2026.