Columbia subject headings:
Harvard subject headings:
Forced labor--Austria--Vienna--History--20th century.
Foreign workers--Austria--Vienna--History--20th century.
National socialism and labor--Austria--Vienna--History--20th century.
Street-railroads--Austria--Vienna--History--20th century.
Wiener Stadtwerke. Wiener Linien--History--20th century.
Princeton subject headings:
Forced labor--Austria--Vienna--History--20th century.
Foreign workers--Austria--Vienna--History--20th century.
National socialism and labor--Austria--Vienna--History--20th century.
Street-railroads--Austria--Vienna--History--20th century.
Wiener Stadtwerke. Wiener Linien--History--20th century.