COSTANDIN, Marius; DOBRA, Petru; GAVREA, Bogdan. A new proof of Ackermann’s formula from control theory. Studia Universitatis Babeș-Bolyai Mathematica, [S. l.], v. 62, n. 3, p. 325–329, 2017. DOI: 10.24193/subbmath.2017.3.05. Disponível em: https://studia.reviste.ubbcluj.ro/index.php/subbmathematica/article/view/1838. Acesso em: 5 feb. 2025.