1. Content composed of information and knowledge needed by the reader.
2. Presentation of information and knowledge in a specific mode of expression, including text, images, symbols, audio, video, and code. Multimedia publications are publications that simultaneously use multiple of these modes of expression on a single medium.
3. A specific physical carrier as the basis for the existence of knowledge and information.
4. A specific production method to attach knowledge and information to the physical carrier.
5. Presentation in a specific visual form. Printed publications, records, audio tapes, video tapes, laser discs, and other audio-visual publications; microfilm and other microfiche publications; and electronic publications such as disks and optical discs are common forms of publication presentation.
