Columbia subject headings:
Art galleries, Commercial--Belgium--Guidebooks.
Art galleries, Commercial--Luxembourg--Guidebooks.
Art museums--Belgium--Guidebooks.
Art museums--Luxembourg--Guidebooks.
Belgium--Description and travel--Guidebooks.
Belgium--Guidebooks.
Luxembourg--Guidebooks.
Museums--Belgium--Guidebooks.
Museums--Luxembourg--Guidebooks.
Harvard subject headings:
Belgium--Guidebooks.
Luxembourg--Guidebooks.
Princeton subject headings:
Belgium--Guidebooks.
Guidebooks.
Luxembourg--Guidebooks.