A. Ciapponi,A. Lee,A. Bardach,D. Glujovsky,L. Rey-Ares,M. Luisa Cafferata,P. Valanzasca and S. García Martí. Interchangeability between Pneumococcal Conjugate Vaccines: A Systematic Review and Meta-Analysis. Value Health Reg Issues. 2016;11:10.1016/j.vhri.2015.12.001.