@misc{misc105ca8b9,
title   = {Re: " Should meta-analyses of interventions include observational studies in addition to randomized controlled trials?: a critical examination of underlying principles". [Carta]},
author = {Pereira, Carlos Alberto de Bragança and Castilho, Euclides Ayres de},
year = {2009},
doi = {10.1093/aje/kwp016},
journal   = {American Journal of Epidemiology}
}