[On the state of the upper respiratory tract in workers in the shale industry in the Estonian SSR].
D006801:Humans; D007221:Industry; D007251:Influenza, Human; D007830:Larynx; D009787:Occupational Medicine; D012129:Respiratory Function Tests; D012141:Respiratory Tract Infections
INDUSTRIAL MEDICINE; INFLUENZA; RESPIRATORY FUNCTION TESTS; RESPIRATORY TRACT INFECTIONS