TA Engineering (General). Civil engineering (General) 22 TK Electrical engineering. Electronics Nuclear engineering 22 TJ Mechanical engineering and machinery 18 QA75 Electronic computers. Computer science 11 QA Mathematics 7 QA76 Computer software 7 HD28 Management. Industrial Management 6 T Technology (General) 6 TP Chemical technology 6 TH Building construction 4 G70.212-70.215 Geographic information system 3 HD Industries. Land use. Labor 3 HD1394-1394.5 Real estate management 3 LB Theory and practice of education 3 QC Physics 3 HF Commerce 2 L Education (General) 2 P Philology. Linguistics 2 QE Geology 2 TD Environmental technology. Sanitary engineering 2 Unspecified 2 BP Islam. Bahaism. Theosophy, etc 1 G Geography (General) 1 GE Environmental Sciences 1 H Social Sciences (General) 1 HB615-715 Entrepreneurship. Risk and uncertainty. Property 1 HC Economic History and Conditions 1 HE Transportation and Communications 1 JA Political science (General) 1 K Law (General) 1