Columbia subject headings:
Art--Germany--Frankfurt am Main--Catalogs.
Communication in art--Catalogs.
Letters in art--Catalogs.
Museumsstiftung Post und Telekommunikation--Catalogs.
Harvard subject headings:
Art--Germany--Frankfurt am Main--Catalogs.
Communication in art--Catalogs.
Letters in art--Catalogs.
Museumsstiftung Post und Telekommunikation--Catalogs.
Princeton subject headings:
Art--Themes, motives--Catalogs.
Catalogs.
Letters in art--Catalogs.
Museumsstiftung Post und Telekommunikation--Art collections--Catalogs.
Postal service in art--Catalogs.
Telecommunication in art--Catalogs.