PURWANINGSIH, S. . Ground State Energy of the Helium Using Variational Methods on Trial Wave Functions. International Journal of Sciences: Basic and Applied Research (IJSBAR), [S. l.], v. 54, n. 4, p. 233–241, 2020. Disponível em: https://gssrr.org/index.php/JournalOfBasicAndApplied/article/view/11800. Acesso em: 3 may. 2024.