a. Nature of the supplement:

Updating supplements are those that add or update information contained in the main work. An example is a directory that is issued annually with a semiannual update containing only additions, changes, and deletions to the main work. An updating supplement is intended to be used with the main work.

There are many types of other supplements whose contents are more independent from that of the main serial. Such supplements generally complement the main work by providing different types of related information or focusing on a special feature.

b. Designations.

The designation of a supplement is often critical in determining whether or not to create a separate record for the supplement. Does it have its own numbering or does it merely carry the numbering of the main work? Unfortunately, it is not always possible to determine the numbering pattern from the first supplement encountered and some recataloging and revised record-keeping may be unavoidable.

See also:

17.4. Serial supplements