9SJ Olshansky, MA Rudberg, BA Carries. Trading Off Longer Life for Worsening Health: the Expansion of Morbidity Hypothesis, Journal Aging Health, 1991 (3) : 194 - 216.
10P, KEMPER, CM MURTAUGH Lifetime use of Nursing Home Care [ J ]. New England Journal of Medicine, 1991 (324) :595 -600.