Programmed instruction 336 Teaching machines 24 Mathematics 14 Study and teaching 12 Statistics 10 Accounting 9 Congresses 8 Education 8 Programming 8 Audio-visual education 7 Educational technology 7 Psychology 7 Bibliography 6 Computer-assisted instruction 6 Individualized instruction 6 Management 6 Nursing 6 Chemistry 5 Economics 5 Physics 5 Arithmetic 4 BASIC (Computer program language) 4 Classification, Dewey decimal 4 Cost accounting 4 Data processing 4 Education, Higher 4 Electronic data processing 4 French language 4 Metallurgy 4 Problems, exercises, etc 4