Study guides Examinations 860 Certification 546 Electronic data processing personnel 415 Computer networks 226 English language 149 Microsoft software 135 Examinations, questions, etc 93 Maintenance and repair 78 Problems, exercises, etc 76 Telecommunications engineers 69 Textbooks for foreign speakers 68 Computer technicians 58 Internetworking (Telecommunication) 49 Security measures 45 Automobiles 41 Test of English as a foreign language 39 Operating systems (Computers) 35 Microcomputers 34 International English Language Testing System 33 Microsoft Windows server 33 Computer security 32 Study skills 29 TCP/IP (Computer network protocol) 29 Microsoft Windows (Computer file) 27 Automobile mechanics 26 Management 26 Universities and colleges 24 Study and teaching 21 Telecommunication 19