Jumadil Saputra, Siti Aisyah Saat,. “A Study of Sustainable Management of Solid Waste in Perhentian Island, Malaysia”. Opción 350 (August 13, 2019): 239-253. Accessed December 5, 2025. https://produccioncientificaluz.org/index.php/opcion/article/view/24696.