Rex Tillerson (L), chairman and chief executive officer of

Rex Tillerson (L), chairman and chief executive officer of Exxon Mobile, shakes hands with Algeria's Minister of Energy and Mines Chakib Khelil at the end of a plenary session during the 19th World Petroleum Congress in Madrid, July 1, 2008. The World Petroleum Congress, which is held every three years, will last until July 3.
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