Oliva J, Hernández CE. Serotypes of Streptococcus pneumoniae in children younger than 5 years after conjugate pneumococcal vaccines. Alerta (San Salvador) [Internet]. 2018 Jun. 29 [cited 2025 Dec. 6];1(1):11-7. Available from: https://www.camjol.info/index.php/alerta/article/view/6585