Eng Tek, O., and J. Abdul Rahim. “Mastery Level of Integrated Science Process Skills (PES) Among the Form 2 Students in Temerloh (80 - 99)”. Jurnal Pendidikan Bitara UPSI, vol. 3, no. 1, May 2019, pp. 80-99, https://ojs.upsi.edu.my/index.php/JPB/article/view/2394.