9Koivula I,Stén M,Makela PH.Prognosis after community-acquired pneumonia in the elderly:a population-basd 12-year follow-up study.Arch Intern Med,1999,159(14):1550-1555.
10Fry AM,Shay DK,Holman RC,et al.Trends in hospitalizations for pneumonia among persons aged 65 years of older in the United States,19882002.JAMA,2005,294(21):2712-2719.
