CHENGJUN SUN. Some Problems of Vaccination Campaigns in Developing Countries. Vaccination Research, [S. l.], v. 1, n. 1, p. e1-e2, 2016. DOI: 10.17140/VROJ-1-e001. Disponível em: https://openventio.us/index.php/VR/article/view/41. Acesso em: 14 nov. 2026.