Saad, N. S. “Pengintegrasian Komponen Pengetahuan Pedagogi Isi Kandungan (PCK) Dalam Pengajaran Pembelajaran Trigonometri: The Integration of Pedagogical Content Knowledge Components in The Teaching and Learning of Trigonometry”. Journal of Science and Mathematics Letters, vol. 1, no. 1, June 2009, pp. 72-83, https://ojs.upsi.edu.my/index.php/JSML/article/view/328.