; . Jurnal Ilmiah Sains, [S. l.], v. 11, n. 2, p. 161–165, 2011. DOI: 10.35799/jis.11.2.2011.201. Disponível em: https://ejournal.unsrat.ac.id/v3/index.php/JIS/article/view/201. Acesso em: 17 mei. 2024.