...
Segregate physically by medium; then by format; then by sub-format (typically, speed and/or size); and finally alphabetically by title. Materials are arranged by format and not intellectually because different media, formats, and sub-formats have different preservation requirements. Two copies of the same title (for example, the recording of a song) might therefore be separated physically from each other if one is on an audiocassette and the other on a vinyl LP. The The two may be brought together intellectually in the finding aid, however, in various ways:
...