A note about FRBR
FRBR (or the Functional Requirements for Bibliographic Records to give it its full title) is an activity within the library community to produce a "framework that [provides] a clear, precisely stated, and commonly shared understanding of what it is that the bibliographic record aims to provide information about, and what it is that we expect the record to achieve in terms of answering user needs".
Full information about FRBR is available at http://www.ifla.org/VII/s13/frbr/frbr.htm.
FRBR models the bibliographic world using 4 key entities - 'Work', 'Expression', 'Manifestation' and 'Item'.
A work is a distinct intellectual or artistic creation. A work is an abstract entity
An expression is the intellectual or artistic realization of a work in the form of alpha-numeric, musical, or choreographic notation, sound, image, object, movement, etc., or any combination of such forms. An expression is the specific intellectual or artistic form that a work takes each time it is "realized."
A manifestation is the physical embodiment of an expression of a work. The entity defined as manifestation encompasses a wide range of materials, including manuscripts, books, periodicals, maps, posters, sound recordings, films, video recordings, CD-ROMs, multimedia kits, etc.
An item is a single exemplar of a manifestation. The entity defined as item is a concrete entity.
FRBR also defines a set of additional entities that are related to the four entities above - 'Person', 'Corporate body', 'Concept', 'Object', 'Event' and 'Place' - and a set of relationships between each of the entities.
In the context of the description of scholarly publications, the key entity-relations appear to be:
- Work -- is realized through --> Expression
- Expression -- is embodied in --> Manifestation
- Manifestation -- is exemplified by --> Item
- Work -- is created by --> Person or Corporate Body
- Manifestation -- is produced by --> Person or Corporate Body
- Expression -- has a translation --> Expression
- Expression -- has a revision --> Expression
- Manifestation -- has an alternative --> Manifestation
Simple metadata standards like Dublin Core have traditionally tended to model the resources being described in a rather flat way - for example, as a set of relatively unrelated 'document-like objects'. While this approach may be sufficient in the context of describing Web pages, it is rather limited in those cases, like scholarly publications, where the things being described are more complex. For example, a typical eprint (the publisher's PDF file that is deposited in an eprint archive) is a single item that is an exemplar of a particular manifestation (the PDF manifestation) of a particular expression (the published version) of a work (the conceptual work that is the eprint). There may be other items that are exemplars of the same manifestation (the PDF file as served from the publisher's Web site for example), other manifestations of the same expression (the HTML manifestation), and other expressions of the same work (the pre-print for example), and so on.
Maintaining knowledge about this relatively complex set of entities may seem like overkill, but without it it will not be possible for software to recognise that a hypertext link between any two items serves much the same function as a traditional citation between the two corresponding expressions. Nor will it be possible for software to respond to end-user requests like "give me the URL of the most appropriate copy (an item) of the PDF format (a manifestation) of the pre-print (an expression) for this eprint (the work)".