Sputum induction as a research tool for the study of human respiratory mucus - Albertini-Yagi, Claudia S.; Oliveira, Regiani C.; Vieira, Joaquim Edson; Negri, Elnara M.; Oliveira, Luciana R. de; Saldiva, Paulo Hilário Nascimento; Lorenzi-Filho, Geraldo (Respiratory Physiology & Neurobiology, 2005)