Purwaningsih, S. . (2020) “Ground State Energy of the Helium Using Variational Methods on Trial Wave Functions”, International Journal of Sciences: Basic and Applied Research (IJSBAR), 54(4), pp. 233–241. Available at: https://gssrr.org/index.php/JournalOfBasicAndApplied/article/view/11800 (Accessed: 3 May 2024).