English language 50 Problems, exercises, etc 43 Foreign speakers 33 Study and teaching 33 Textbooks for foreign speakers 32 Leadership 8 Management 6 Sound recording for foreign speakers 6 Spoken English 5 Juvenile literature 4 History 3 National security 3 Personnel management 3 Air power 2 Armed Forces 2 Congresses 2 Economic development 2 Economic policy 2 Electronic commerce 2 Entrepreneurship 2 Government policy 2 Human capital 2 Organizational change 2 Spoken english 2 Strategic planning 2 Swords 2 Textbook for foreign speakers 2 Training of 2 Z1 2 1945- 1