Columbia subject headings:
Architecture--Malta--Valletta.
Art--Malta--Valletta.
Valletta (Malta)--History.
Harvard subject headings:
Architecture--Malta--Valletta--Congresses.
Art, Italian--Malta--Valletta--Congresses.
Fortification--Malta--Valletta--Congresses.
Valletta (Malta)--Buildings, structures, etc.--Congresses.
Valletta (Malta)--History--Congresses.
Princeton subject headings:
Architecture--Malta--Valletta--Congresses.
Fortification--Malta--Valletta--Congresses.
Valletta (Malta)--Buildings, structures, etc.--Congresses.
Valletta (Malta)--History--Congresses.