16 INSTRUCTIONAL AND TEACHING MATERIALS SOLD AS A UNIT COMPRISED OF TEXTBOOKS IN THE FIELD OF LANGUAGE ARTS, FOREIGN LANGUAGES, NATURAL AND PHYSICAL SCIENCES, MATHEMATICS, SOCIAL SCIENCES, FINE ARTS AND APPLIED ART, WORKBOOKS, VIDEO DISKS, VIDEO AND AUDIO LASER DISKS, AUDIO TAPES, VIDEO TAPES AND COMPUTER PROGRAMS IN THE FIELD OF LANGUAGE ARTS FOREIGN LANGUAGES, NATURAL AND PHYSICAL SCIENCES, MATHEMATICS, SOCIAL SCIENCES, FINE ARTS AND APPLIED ARTS