Keeping in touch with the elderly: Lifeline.
D000368:Aged; D003625:Data Collection; D004631:Emergency Medical Service Communication Systems / Q000191:economics*; D004632:Emergency Medical Services / Q000191:economics*; D006299:Health Services for the Aged; D006741:Hospital Auxiliaries; D006758:Hospital Volunteers; D006801:Humans; D014481:United States