2.5B9.

Interpret the phrase "publications that are designed to receive additions" to cover publications for which the additions or replacements are to be interfiled within the existing text. For this and other matters relating to loose-leaf publications, see Adele Hallam’s Cataloging Rules for the Description of Looseleaf Publications, prelim. notes and rule 5B1.

See also:

2.5B. Number of volumes and/or pagination