Zahari, Nurnadhirah, Zulhan Othman, Nor Adila Kedin, Azdel Abdul Aziz, and Mohd Faeez Saiful Bakhtiar. “Tipping Practices, Employee Motivation and Service Delivery Performance Among 4 and 5-Star Hotel Employees in Penang”. Information Management and Business Review 17, no. 4(I) (November 23, 2025): 10-18. Accessed October 17, 2026. https://ojs.amhinternational.com/index.php/imbr/article/view/4512.