Columbia subject headings:
Harvard subject headings:
Emigration and immigration--Political aspects
Illegal immigration--Communist countries.
Noncitizens--Communist countries.
Poland--Emigration and immigration
Poland--Politics and government--1945-1980
Political persecution--Communist countries.
Refugees--Poland.
Princeton subject headings:
Poland--Emigration and immigration.
Poland--Politics and government--1945-1980.
Political persecution--Poland.