Petroleum industry and trade History 54 Political aspects 47 Government policy 31 Energy policy 28 Gas industry 28 Politics and government 26 more ... Environmental aspects 20 Petroleum 19 Petroleum reserves 18 Economic aspects 17 Economic conditions 17 Petroleum engineering 15 Foreign relations 14 Social aspects 13 Petroleum products 12 Prices 12 Industria petrolera 11 Econometric models 10 Energy consumption 10 Foreign economic relations 10 Petroleo 10 Social conditions 9 Fiscal policy 7 Natural gas 7 Economic development 6 Management 6 World politics 6 Economic policy 5 Energy industries 5 less ...