Columbia subject headings:
Harvard subject headings:
Ploner, Georg, 1821-1907.
Tourism--Alps--History--19th century.
Tourism--Italy--Trentino-Alto Adige--History--19th century.
Princeton subject headings:
Ploner, Georg, 1821-1907.
Tourism--Alps--History--19th century.
Tourism--Italy--Trentino-Alto Adige--History--19th century.