Columbia subject headings:
Asociación CARBOCOL-INTERCOR--History--Sources.
CARBOCOL (Corporation)--History--Sources.
Coal trade--Colombia--Ejón Hill Region--History--Sources.
INTERCOR (Corporation)--History--Sources.
Harvard subject headings:
Asociación CARBOCOL-INTERCOR--History--Sources.
Carbones de Colombia S.A.--History--Sources.
Coal trade--Colombia--Ejón Hill Region--History--Sources.
International Colombia Resources Corporation--History--Sources.
Princeton subject headings: