Overall function of the elements of the description of an expression:
- To enable a catalog user to distinguish one expression of a particular work from another in order to facilitate the choice of an expression of a sought work.
- To enable a catalog user to identify a particular expression of a particular work that is being sought.
- To characterize the nature of a particular expression of a particular work in order to facilitate the user's choice of either work or expression.
Since the user of the catalog rarely knows all of the following details about the expression being sought, and since in growing collections it cannot be foreseen which of these details will be necessary to distinguish the various expressions to be acquired in the future, it is essential to include all of the following elements in the description.
The principle of transcription as applied to an expression: Transcription (a copy of the text that appears on the item) will actually be taken from a particular item that is an exemplar of a particular manifestation of a particular expression. Transcribed data elements linked to an expression implicitly convey to the user the information that all linked manifestations and items will carry this transcribed information. When this is not the case, different title and statement of responsibility information should be treated as a title-manifestation (discussed above); different distribution information on subsequent manifestations should be recorded at the manifestation level (see below).
Elements of the description of an expression: