Ngoc Long, H., 		Van Vien, V., & 		Hoa Binh, V.
(2021).
 Effective Couplings between Two Photons and Axion  in the 3-3-1 Model.
<em>VNU Journal Of Science: Mathematics - Physics, 37</em>(4).
doi:10.25073/2588-1124/vnumap.4627