PINGAK, Redi Kristian; KOLMATE, Rosara; BERNANDUS, Bernandus. A Simple Matrix Approach to Determination of the Helium Atom Energies. Jurnal Penelitian Fisika dan Aplikasinya (JPFA), [S. l.], v. 9, n. 1, p. 10–21, 2019. DOI: 10.26740/jpfa.v9n1.p10-21. Disponível em: https://journal.unesa.ac.id/index.php/jpfa/article/view/2711. Acesso em: 30 jun. 2025.