Prevalence of respiratory symptoms in an unpolluted area of northern Italy
G Viegi, P Paoletti, R Prediletto, L Carrozzi, P Fazzi, F Di Pede, G Pistelli, C Giuntini, MD Lebowitz
European Respiratory Journal 1988 1: 311-318; DOI: 10.1183/09031936.93.01040311