History 106 Social workers 29 Emigration and immigration 28 Social conditions 21 Civil rights workers 20 African Americans 19 Foreign workers 19 White collar workers 19 Civil rights 17 Economic aspects 17 Race relations 17 Civil rights movements 16 Labor unions 16 Trade-unions 15 Volunteer workers in social service 15 Automobile industry workers 13 Construction workers 13 Social service 12 Employment 11 Foreign workers, Chinese 11 Knowledge workers 11 Service industries workers 11 Case studies 10 Employees 10 Chinese 9 Social aspects 9 Textile workers 9 Women foreign workers 8 African American civil rights workers 7 Human rights workers 7