Congresses 24 History 11 Economic conditions 7 Research 5 Study and teaching 5 Education 4 History and criticism 4 Politics and government 4 Economic policy 3 Mathematical models 3 Administration 2 Adult education 2 Biography 2 Case studies 2 Commerce 2 Cotton machinery 2 Cotton manufacture 2 Criticism and interpretation 2 Economic aspects 2 Electric engineering 2 English poetry 2 Exhibitions 2 French language 2 Housing 2 Information storage and retrieval systems 2 Law 2 Museums 2 Periodicals 2 Pricing 2 Railroads 2