Columbia subject headings:
Olmec art--Congresses.
Olmecs--Antiquities--Congresses.
Harvard subject headings:
Excavations (Archaeology)--Mexico--Congresses.
Mexico--Antiquities--Congresses.
Olmec art--Congresses.
Olmecs--Antiquities--Congresses.
Princeton subject headings:
Olmec art--Congresses.
Olmecs--Antiquities--Congresses.