Architecture 20 History of architecture 11 Theory of architecture 7 Urban & municipal planning 7 City & town planning - architectural aspects 5 Environmentally-friendly architecture & design 5 History 5 Urban communities 5 Anthropology 4 Architecture: professional practice 4 Public buildings: civic, commercial, industrial, etc 4 Sociology 4 Algorithms & data structures 3 Architectural structure & design 3 Business mathematics & systems 3 Expert systems / knowledge-based systems 3 Finance 3 Individual architects & architectural firms 3 Landscape art & architecture 3 Migration, immigration & emigration 3 Software Engineering 3 Sustainability 3 Systems analysis & design 3 The arts 3 Applied ecology 2 Biography: arts & entertainment 2 Biography: general 2 Climate change 2 Computer security 2 Development economics & emerging economies 2