Methodological issues on planning and running the brazilian multicenter study on preterm birth - Lajos, Giuliane J; Tedesco, Ricardo P; Passini Junior, Renato; Dias, Tabata Z; Nomura, Marcelo L; Rehder, Patrícia M; Haddad, Samira M; Sousa, Maria H; Cecatti, Jose G; Martinez, Francisco Eulógio; Quintana, Silvana Maria (The Scientific World Journal, 2015)