Phu Vinh, Nguyen, and Nguyen Dinh Tung. 2004. “THE AREA FORMULA OF POLYGON FOR THREE DIMENSIONAL, VOLUME OF POLYGON AND THE APPLICATION TO DESIGN A NET IN FINITE ELEMENT METHOD”. VNUHCM Journal of Science and Technology Development 7 (7), 5-11. https://doi.org/https://doi.org/10.32508/stdj.v7i7.3224.