Columbia subject headings:
Documentary photography--Spain--Madrid--History--20th century.
González Ragel, Diego.
Madrid (Spain)--History--20th century--Pictorial works.
Harvard subject headings:
Documentary photography--Spain--Madrid--History--20th century.
González Ragel, Diego, 1893-1951.
Madrid (Spain)--History--20th century--Pictorial works.
Princeton subject headings:
Documentary photography--Spain--Madrid--History--20th century.
González Ragel, Diego.
Madrid (Spain)--History--20th century--Pictorial works.