Soa, Dang Van, and Tran Dinh Tham. “Axion in a 3-3-1 Model With Right-Handed Neutrinos”. Communications in Physics 23, no. 3 (December 6, 2013): 283. Accessed April 25, 2024. https://vjs.ac.vn/index.php/cip/article/view/3378.