Audio-visual aids 139 Audio-visual education 126 Study and teaching 78 Visual perception 57 Audio-visual materials 54 Catalogs 46 Bibliography 35 Audio-visual equipment 34 Teaching 33 Aids and devices 30 Education 24 Audio-visual library service 23 Congresses 21 BASIC (Computer program language) 20 People with visual disabilities 14 Flow visualization 13 Visual education 13 Languages, Modern 12 Libraries 12 Special collections 12 Children with visual disabilities 11 Blind 10 Educational technology 10 Nonbook materials 10 Visual communication 10 Art 9 Data processing 9 French language 9 Instructional materials centers 9 Programmed instruction 9