NGO, Thi Thanh Nga. A new approach to the index of differential-algebraic equations based on the index of matrix pencil. Thang Long Journal of Science: Mathematics and Mathematical Sciences, [S. l.], v. 5, n. 1, 2026. Disponível em: https://science.thanglong.edu.vn/index.php/volc/article/view/295. Acesso em: 27 apr. 2026.