Ngaonaseaw, P. “A Study of Knowledge and Understanding of Travel Expense Regulations and Problems in Preparation of Travel Expense Documents for Staff at Maejo University, Chiang Mai Province”. RPU Journal of Business Administration, vol. 4, no. 2, Dec. 2025, pp. 380-96, https://so03.tci-thaijo.org/index.php/RPUBAJOURNAL/article/view/296548.