Columbia subject headings:
Harvard subject headings:
Poland--Politics and government--1945-1980--Sources.
Strikes and lockouts--Poland
Strikes and lockouts--Poland--Chronology.
Strikes and lockouts--Poland--Sources.
Princeton subject headings:
Strikes and lockouts--Poland--Gdańsk.
Strikes and lockouts--Poland--Gdynia.
Strikes and lockouts--Poland--Szczecin.
Strikes and lockouts--Poland--Łódź.