Land use Planning 158 Regional planning 121 Economic conditions 65 City planning 60 Agriculture 39 Congresses 32 Economic aspects 32 Law and legislation 32 Environmental aspects 24 Natural resources 24 Data processing 21 Periodicals 20 Government policy 19 History 18 Land tenure 18 Conservation of natural resources 17 Information storage and retrieval systems 17 Information services 16 Nature conservation 15 Real property 14 Bibliography 13 Soils 13 Public lands 12 Soil conservation 12 Mathematical models 11 Real estate development 11 Cities and towns 10 Management 10 Transportation 9