Columbia subject headings:
Harvard subject headings:
Excavations (Archaeology)--Spain--Congresses
Quarries and quarrying--Spain--Congresses.
Spain--Antiquities--Congresses.
Princeton subject headings:
Excavations (Archaeology)--Spain--Congresses.
Quarries and quarrying--Spain--History--Congresses.
Romans--Spain--Congresses.
Spain--Antiquities, Roman--Congresses.
Stone industry and trade--Spain--History--Congresses.