Laddawan Dokkaew และ Pramuk Osiri. (2015) Prevalence and factors associated with respiratory symptoms and pulmonary function among solid waste collectors of Bangkok metropolitan adminstration. Mahidol University:ม.ป.ท.Laddawan Dokkaew และ Pramuk Osiri. 2015. Prevalence and factors associated with respiratory symptoms and pulmonary function among solid waste collectors of Bangkok metropolitan adminstration. ม.ป.ท.:Mahidol University;Laddawan Dokkaew และ Pramuk Osiri. Prevalence and factors associated with respiratory symptoms and pulmonary function among solid waste collectors of Bangkok metropolitan adminstration. ม.ป.ท.:Mahidol University, 2015. Print.