title: Study of man during a 56-day exposure to an oxygen-helium atmosphere at 258 mm. hg total pressure. XIV. Communications.
mesh_terms: D000531:Altitude; D001274:Atmospheric Pressure; D018504:Ecological Systems, Closed; D004781:Environmental Exposure; D006371:Helium; D006801:Humans; D008297:Male; D009622:Noise; D010100:Oxygen; D012119:Respiration; D013060:Speech; D014705:Verbal Behavior
chemical_list: D006371:Helium; D010100:Oxygen