THUY, Nguyen Xuan. Concerning semi-quotient mappings. VNU Journal of Science: Mathematics - Physics, [S.l.], v. 28, n. 2, june 2012. ISSN 2588-1124. Available at: <https://js.vnu.edu.vn/MaP/article/view/952>. Date accessed: 06 apr. 2025.