Columbia subject headings:
Harvard subject headings:
National socialism--Germany--Rhineland.
National socialism--Germany--Westphalia.
Rhineland (Germany)--Ethnic relations--History--20th century.
Romanies--Nazi persecution--Germany--Rhineland.
Romanies--Nazi persecution--Germany--Westphalia.
Westphalia (Germany)--Ethnic relations--History--20th century.
Princeton subject headings:
Romanies--Nazi persecution--Germany--North Rhine-Westphalia.