Yunus, Faizal Amin Nur, et al. “Elements of Competency for Facility Engineers in The Field of Refrigeration and Air Conditioning”. Online Journal for TVET Practitioners, vol. 7, no. 2, Oct. 2022, pp. 38-43, https://penerbit.uthm.edu.my/ojs/index.php/oj-tp/article/view/11407.