ULLAH, R.; ASHRAF, S. Chronic obstructive lung disease: A rising problem for the world. Pakistan Journal of Chest Medicine, [S. l.], v. 23, n. 4, p. 130–33, 2018. Disponível em: https://pjcm.net/index.php/pjcm/article/view/481. Acesso em: 1 nov. 2025.