History 227 Land tenure 86 History and criticism 81 Architecture 67 Historia 65 Philosophy 64 Arquitectura 63 more ... Education 58 Educación 52 General 50 urban and land use planning 50 Politics and government 48 Filosofía 39 Social aspects 39 Social conditions 37 Planificación urbana y uso de las tierras 36 Law and legislation 35 Criticism and interpretation 32 Land reform 32 Tenencia de la tierra 32 Land use 31 Study and teaching 28 Indians of South America 27 Law 26 Science 26 Research 25 Spanish literature 25 Medicina 24 Ciencias sociales 23 Economic conditions 22 less ...