QA76 Computer software 233 QA75 Electronic computers. Computer science 19 HD28 Management. Industrial Management 13 TA Engineering (General). Civil engineering (General) 8 HE Transportation and Communications 7 HF Commerce 6 T Technology (General) 5 TK Electrical engineering. Electronics Nuclear engineering 5 HD Industries. Land use. Labor 4 Q Science (General) 3 TP Chemical technology 3 H Social Sciences (General) 2 L Education (General) 2 LB Theory and practice of education 2 TD Environmental technology. Sanitary engineering 2 TJ Mechanical engineering and machinery 2 TS Manufactures 2 GA Mathematical geography. Cartography 1 HG Finance 1 LB1603 Secondary Education. High schools 1 LB2300 Higher Education 1 NA Architecture 1 RZ Other systems of medicine 1 TC Hydraulic engineering. Ocean engineering 1 TE Highway engineering. Roads and pavements 1 Z665 Library Science. Information Science 1 Z719 Libraries (General) 1