5CHEN Y P. “Equivalent Retirement Ages” and theirimplications for social security and medicare financing[J]. The Gerontologist, 1994,34(6) :731 - 735.
6GRUBER J, MILLIGAN K, WISE D A. Social securityprograms and retirement around the world : therelationship to youth employment, introduction andsummary[J], Nber Working Papers, 1997, 74 (99) :904-906.
7KALWIJ A, KAPTEYN A, DE VOS K. Retirement ofolder workers and employment of the young [J]. DeEconomist,2010,158(4) :341 - 359.