ALBEVERIO, S.; NIZHNIK, L. P. Approximation of general zero-range potentials. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 52, n. 5, p. 582–589, 2000. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/4452. Acesso em: 5 dec. 2025.