(MUD), when it was formed as the coalition of the opposition parties ofVenezuela, to face the government of the late Hugo Chávez . But it has been a difficult
Brownfield & Janet K. Pitman. An Estimate of Recoverable Heavy Oil Resources of the Orinoco Oil Belt, Venezuela (PDF). USGS. 2010-01-11 [2010-01-23]. (原始内容存档