Maternal pregnancy smoking in three Brazilian cities: trends and differences according to education, income, and age - Mola, Christian Loret de; Cardoso, Viviane Cunha; Batista, Rosangela; Gonçalves, Helen; Saraiva, Maria da Conceição Pereira; Menezes, Ana M. B.; Santos, Iná S.; Domingues, Marlos Rodrigues; Silva, Antonio Augusto Moura da; Bettiol, Heloisa; Alves, Maria Teresa Seabra Soares de Britto e; Barbieri, Marco Antonio; et al. (International Journal of Public Health, 2020)