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The analysis of social systems
Bredemeier, Harry C., (1962)
Ensuring health and income security for an aging workforce
Budetti, Peter P., (2001)
Deutsch-Amerikanischer Transatlantischer Dialog: Zukunft der Arbeitsgesellschaft, Zukunft der Sozialpolitik
Greifenstein, Ralph, (2000)
Introduction to the mathematics of population
Keyfitz, Nathan, (1977)
Population change and social policy
Keyfitz, Nathan, (1982)
Urban influence on farm family size
Keyfitz, Nathan, (1980)