Maintenance and repair Automobiles 31 Airplanes 17 Thesis 14 Dwellings 12 Microcomputers 11 Dissertations, Academic 8 Amateurs' manuals 7 Design and construction 7 Upgrading 7 Equipment and supplies 6 Ships 6 Boats and boating 5 Handbooks, manuals, etc 5 Airplane 4 Electric equipment 4 Electronic apparatus and appliances 4 Management 4 Motor vehicles 4 Radar 4 Air conditioning 3 Airlines 3 Building 3 Electric apparatus and appliances 3 Examinations, questions, etc 3 Maintenance 3 Motors 3 Reliability (Engineering) 3 Remodeling 3 Amateur's manal 2