The origins of health insurance for the aged.
D000368:Aged; D000574:American Medical Association; D003695:Delivery of Health Care; D004469:Economics, Hospital; D004470:Economics, Medical; D005380:Financing, Government; D005382:Financing, Personal; D005102:Health Expenditures; D049673:History, 20th Century; D006761:Hospitals / Q000706:statistics & numerical data; D006801:Humans; D007348:Insurance, Health; D007350:Insurance, Hospitalization; D007883:Legislation, Medical / Q000266:history; D007902:Length of Stay; D006278:Medicare / Q000266:history*; D012940:Social Problems; D012943:Social Security; D012952:Societies; D014481:United States