Columbia subject headings:
Frankfurt am Main (Germany)--Pictorial works.
Photography--Germany--Frankfurt am Main--History--19th century.
Portrait photography--Germany--Frankfurt am Main.
Harvard subject headings:
Frankfurt am Main (Germany)--Pictorial works.
Photography, Artistic.
Photography--Germany--Frankfurt am Main.
Princeton subject headings:
Frankfurt am Main (Germany)--Pictorial works.
Photography--Germany (West)--Frankfurt am Main--19th century.