ปานกลาง นิติพงศ์. “Using The 9-DOF Curve Elements for Electric Field Calculation by using The Surface Charge Method”. Frontiers in Engineering Innovation Research 5 (June 30, 2005): 1–5. accessed January 24, 2025. https://ph01.tci-thaijo.org/index.php/jermutt/article/view/242307.