Programmed instruction Teaching machines 21 Mathematics 14 Study and teaching 11 Statistics 10 Accounting 9 Congresses 7 Computer-assisted instruction 6 Education 6 Individualized instruction 6 Management 6 Psychology 6 Audio-visual education 5 Chemistry 5 Economics 5 Educational technology 5 Nursing 5 Programming 5 Arithmetic 4 BASIC (Computer program language) 4 Classification, Dewey decimal 4 Cost accounting 4 Education, Higher 4 Electronic data processing 4 French language 4 Metallurgy 4 Physics 4 Teaching 4 Algebra 3 Audio-visual aids 3