GUSAK, D. V. On the first ruin moment for a modified risk process with immediate reflection. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 50, n. 10, p. 1419–1425, 1998. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/4828. Acesso em: 5 dec. 2025.