title: [Hygienic principles of organizing extracurricular activities of students].
mesh_terms: D000293:Adolescent; D002648:Child; D006801:Humans; D011998:Recreation; D012146:Rest; D012572:School Health Services; D013177:Sports
vernacular_title: Gigienicheskie printsipy organizatsii vneuchebnoĭ deiatel'nosti uchashchikhsia.