Maintenance and repair Roads 56 Design and construction 37 Automobiles 26 Dwellings 23 Boats and boating 18 Equipment and supplies 16 Congresses 15 Management 15 Machinery 13 Pavements 13 Amateurs' manuals 10 Electronic apparatus and appliances 10 Industrial equipment 10 Outboard motors 10 Microcomputers 9 Plant maintenance 9 Costs 8 Fiberglass boats 8 Household appliances, Electric 8 Safety measures 8 Buses 7 Handbooks, manuals, etc 7 Motor vehicles 7 Electric machinery 6 Highway planning 6 Study and teaching 6 Wooden boats 6 Concrete 5 Concrete construction 5