Loan, Doan Thi, Nguyen Hoang Phuc, and Dao Tien Khoa. “R-Matrix Method and the Nonlocal Nucleon Optical Potential”. Communications in Physics 28, no. 4 (December 27, 2018): 323. Accessed September 26, 2021. https://vjs.ac.vn/index.php/cip/article/view/12760.