Occupation and bronchitis.
D001991:Bronchitis / Q000209:etiology*; D003031:Coal; D004391:Dust / Q000517:prevention & control; D005860:Germany, West; D006801:Humans; D008452:Maximum Allowable Concentration; D009784:Occupational Diseases / Q000209:etiology*; D012907:Smoking / Q000150:complications
D003031:Coal; D004391:Dust