The Bibliographic Reference Code is a domain-specific code which was designed to be sufficient for the immediate needs of astronomy in uniquely, succinctly, and informatively identifying bibliographic references. Nevertheless, the REF_CODE proved to be general enough to encompass most of the existing astronomical literature. But these REF_CODEs were not explicitly designed to be so general that they were guaranteed to automatically encompass all presently available media, nor do they necessarily fully anticipate future directions in publishing.
In combination with a descriptive reference database, the cryptic form of the REF_CODE can be (and is) attached to a more extensible information listing. For instance, while the REF_CODE carries only the first page number of a reference, the Reference Database carries the first and last page numbers of the article. Obviously, the same qualifications apply to titles and authors which are highly abbreviated in the REF_CODE, but more fully represented in the Database.
The same principles could be used to fully link a REF_CODE to data cubes, CD-ROMs, external databases, animations, simulations, time-tagged data, etc. While the Reference Code is compact, it is not yet saturated; there are still fields with room for added pointers to the new directions that the publishing of astronomical data may take in the immediate future.