Genetic analyses of smoking initiation, persistence, quantity, and age-at-onset of regular cigarette use in Brazilian families: the Baependi Heart Study - Horimoto, Andréa R. V. R.; Oliveira, Camila M.; Giolo, Suely R.; Soler, Júlia Maria Pavan; Andrade, Mariza de; Krieger, José E.; Pereira , Alexandre C. (BMC Medical Genetics, 2012)