Columbia subject headings:
Art nouveau (Architecture)--Spain--Madrid--Congresses.
Glass painting and staining--Spain--Madrid--History--19th century--Congresses.
Glass painting and staining--Spain--Madrid--History--20th century--Congresses.
Madrid (Spain)--Buildings, structures, etc.--Congresses.
Harvard subject headings:
Art glass--Spain--History--19th century.
Art glass--Spain--History--20th century.
Glass painting and staining--Spain--Madrid--History--19th century.
Glass painting and staining--Spain--Madrid--History--20th century.
Princeton subject headings:
Art nouveau (Architecture)--Spain--Madrid--Congresses.
Glass painting and staining--Spain--Madrid--History--19th century--Congresses.
Glass painting and staining--Spain--Madrid--History--20th century--Congresses.
Madrid (Spain)--Buildings, structures, etc.--Congresses.