NICDH International Site Developmental Initiative (NISDI): a prospective, observational study of HIV-exposed and HIV-infected children at clinical sites in Latin American and Caribbean countries - Hazra, Rohan; Stoszek, Sonia K.; Hance, Laura Freimanis; Pinto, Jorge; Marques, Heloisa; Peixoto, Mario; Alarcon, Jorge; Mussi-Pinhata, Marisa Márcia; Serchuck, Leslie (International Journal of Epidemiology, 2008)