The Prediction of The Drought Index in The Indragiri Watershed Using SARIMA and SPI Methods. Sainmatika: Jurnal Ilmiah Matematika dan Ilmu Pengetahuan Alam, [S. l.], v. 20, n. 1, p. 72–82, 2023. DOI: 10.31851/sainmatika.v20i1.11501. Disponível em: https://jurnal.univpgri-palembang.ac.id/index.php/sainmatika/article/view/11501. Acesso em: 21 jun. 2026.