Columbia subject headings:
Harvard subject headings:
Antofagasta (Chile : Region)--History--Pictorial works.
Chile saltpeter industry--Chile--Antofagasta (Region)--History--Pictorial works.
Chile saltpeter industry--Chile--Tocopilla--History--Pictorial works.
Tocopilla (Chile)--History--Pictorial works.
Princeton subject headings:
Antofagasta (Chile : Region)--History--Pictorial works.
Chile saltpeter industry--Chile--Antofagasta (Region)--History--Pictorial works.
Chile saltpeter industry--Chile--Tocopilla--History--Pictorial works.
Tocopilla (Chile)--History--Pictorial works.