Columbia subject headings:
Excavations (Archaeology)--Spain--Zaragoza.
Sewerage--Spain--Zaragoza--History.
Zaragoza (Spain)--Antiquities, Roman.
Harvard subject headings:
Excavations (Archaeology)--Spain--Zaragoza.
Sewerage--Spain--Zaragoza--History.
Zaragoza (Spain)--Antiquities, Roman.
Princeton subject headings:
Excavations (Archaeology)--Spain--Zaragoza.
Sewerage--Spain--Zaragoza--History.
Zaragoza (Spain)--Antiquities, Roman.