Hashim, Mohmadisa, Wan Ruslan Ismail, Mohamad Suhaily Yusri Che Ngah, Nasir Nayan, Yazid Saleh, and Zahid Mat Said. 2011. “Trend Luahan Tahunan Di LembanganSungai Perak 1915-2006: Sungai Perak’s Catchment Yearly Discharge Trend 1915-2006”. Perspektif Jurnal Sains Sosial Dan Kemanusiaan 3 (2):53-63. https://ejournal.upsi.edu.my/index.php/PERS/article/view/1599.