Columbia subject headings:
European Union--Boundaries.
Poland--Boundaries--Ukraine.
Poland--Relations--Ukraine.
Russo-Ukrainian War, 2014-
Ukraine--Boundaries--Poland.
Ukraine--Relations--Poland.
Harvard subject headings:
European Union--Boundaries.
Poland--Boundaries--Ukraine.
Poland--Relations--Ukraine
Ukraine Conflict, 2014-
Ukraine--Boundaries--Poland.
Ukraine--Relations--Poland
Princeton subject headings:
European Union--Boundaries.
Poland--Boundaries--Ukraine.
Poland--Relations--Ukraine.
Ukraine Conflict, 2014-
Ukraine--Boundaries--Poland.
Ukraine--Relations--Poland.