Columbia subject headings:
Citizenship--Philosophy.
Civilization, Modern--21st century--Philosophy.
Emigration and immigration--Philosophy.
Emigration and immigration--Political aspects.
Emigration and immigration--Social aspects.
Harvard subject headings:
Citizenship--Philosophy
Civilization, Modern--21st century--Philosophy.
Emigration and immigration--Philosophy.
Emigration and immigration--Political aspects
Emigration and immigration--Social aspects
Princeton subject headings:
Emigration and immigration--Philosophy.
Emigration and immigration--Political aspects.
Emigration and immigration--Social aspects.