Petroleum industry and trade History 86 Political aspects 86 Government policy 51 Energy policy 45 Gas industry 41 Politics and government 41 more ... Environmental aspects 39 Foreign relations 27 Economic aspects 23 Petroleum 23 Social aspects 23 Economic conditions 21 Petroleum products 21 Petroleum reserves 21 Prices 21 Petroleum engineering 18 Foreign economic relations 15 Energy consumption 14 Social conditions 14 Econometric models 10 Economic development 10 Natural resources 10 Oil fields 10 Fiscal policy 9 Management 9 Businessmen 8 Economic policy 8 World politics 8 Environmental conditions 7 less ...