Hung, Ha Thanh, Le Tho Hue, and Hoang Ngoc Long. “Ward-Takahashi Identity for Vertex Functions of \(\text{sQED}\)”. Communications in Physics 23, no. 1 (April 10, 2013): 11. Accessed April 25, 2024. https://vjs.ac.vn/index.php/cip/article/view/2604.