Razak, N. A., Z. M. Aminuddin, A. R. Ghazali, and N. H. Asnawi. “Assessing of Customer Perception on Innovation of Food Service”. Journal of Reviews on Global Economics, vol. 8, Dec. 2019, pp. 958-62, https://www.lifescienceglobal.com/pms/index.php/jrge/article/view/6249.