[The permissible duration of weeding work by city schoolchildren in the 11-12 age group].
D000383:Agriculture; D002648:Child; D005221:Fatigue; D006801:Humans; D008297:Male; D011187:Posture; D012572:School Health Services; D013997:Time Factors
K voprosu o dopustimoĭ dlitel'nosti propolochnykh rabot dlia gorodskikh shkol'nikov 11-12 let.