Smoking and respiratory symptoms in two groups of schoolchildren.
D002648:Child; D003371:Cough / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D006306:Health Surveys; D006801:Humans; D008297:Male; D012572:School Health Services; D012907:Smoking / Q000150:complications* / Q000453:epidemiology; D011795:Surveys and Questionnaires; D006113:United Kingdom