Chronic productive cough in young adults is very often due to chronic rhino-sinusitis oleh A.G. Corsico, S. Villani, M.C. Zoia, R. Niniano, E. Ansaldo, G. Cervio, P.M. Quaresima, E. Gatto, E. Crippa, A. Marinoni, A. Foresi, E. Pozzi, I. Cerveri