Wang Guilian,Jining. “THE IMPORTANT POSITION AND EFFECTS OF PIANGUAN IN THE DEFENSE SYSTEM OF THE MING GREAT WALL”. Ethiopian International Journal of Multidisciplinary Research, vol. 11, no. 02, Feb. 2024, pp. 53-57, https://www.eijmr.org/index.php/eijmr/article/view/1042.