Soviet Union 282 History 175 Foreign relations 88 Politics and government 73 India 66 Library classification schemes 65 Economics 45 Education 45 Agriculture 44 Finance 43 Colonization 39 Population 39 Industries 38 Non-governmental organizations 37 Rural development 37 United States 37 Communication 36 Language and literature 36 Scheduled tribes 36 Transportation 36 Tribes 36 Untouchables 36 Wildlife management 36 Tourist trade 35 Urbanization 35 Labor economics 33 Trade unions 32 Government 30 Politics 28 China 27