วรรธนะภูติ อ. (2017) “A MATHEMATICAL MODEL : OPTIMIZING ORDERING OF IMPORT BUSINESS IN TRADING PATTERN”, Modern Management Frontier Journal, 15(1), pp. 149–160. available at: https://so04.tci-thaijo.org/index.php/stou-sms-pr/article/view/68735 (accessed: 28 September 2026).