Appropriate technology Technology 13 Congresses 5 Social aspects 5 Directories 4 Economic development 4 Case studies 3 Human ecology 3 Renewable energy sources 3 Rural development 3 Technological innovations 3 Technology transfer 3 Agricultural implements 2 Agriculture 2 Economic aspects 2 Economic assistance 2 Economic conditions 2 Economies of scale 2 Environmental protection 2 Social change 2 Societies, etc 2 Architecture 1 Basic needs 1 Bibliography 1 Bicycle industry 1 Biogas 1 Building materials 1 Buildings 1 Community development 1 Conservation of natural resources 1