Petroleum industry and trade -- Political aspects -- 10 Government policy -- 9 Political aspects 9 Energy policy -- 8 Gas industry -- 6 History -- 6 more ... Economic conditions -- 5 Foreign relations -- 5 Politics and government 5 Politics and government -- 5 World politics -- 5 Economic aspects 4 Economic conditions 4 Energy industries -- 4 Energy policy 4 Petroleum industry and trade 4 Congresses 3 Congresses -- 3 Economic policy 3 Environmental aspects -- 3 History 3 Addresses, essays, lectures 2 Asia 2 China 2 Diversification in industry -- 2 Environmental aspects 2 Environmental policy -- 2 Forecasting -- 2 Foreign economic relations 2 less ...