The information in this document is helpful and well written, but
leaves as many questions as it answers.

"The nuclear set of BIBFRAME Work records are then augmented with the
subject information found in the MARC Bibliographic records that carry
those work titles in their 130/240 uniform title fields.  In addition
class numbers (but not call numbers*) are carried over as additional
subject information and the content type is derived from MARC Leader
positions and the 336 fields. Since MARC had several places where
content type may be recorded, there may be several content type
indications in the BIBFRAME Work record.  If the new BIBFRAME Work
record contains certain elements in the heading string (e.g., language
or arr. subfields) the records are identified by the programs as RDA
Expression records so several additional elements native to RDA
Expressions are also included in the BIBFRAME Work record, in addition
to the links indicated above."

*I assume from this class/call number distinction, Cutters will not be
carried over to work records.  What about LCC subject and geographic
Cutters?  Will all class numbers be carried over, including NLMC,

"The BIBFRAME Instance dataset is generated from the MARC
bibliographic records.  Every MARC bibliographic record creates one or
more BIBFRAME Instance records.  The program uses several clues to
generate more than one instance record from one MARC bibliographic in
certain situations, e.g., some cases where multiple ISBNs are present
in the bibliographic record, or cases where there is an indication
that a microform and a print or an electronic and a print are
represented on the same bibliographic record.  The Instance records
are then generated for all of the identified Instances and include the
elements that have been identified generally for RDA Manifestations
such as physical description information, provider information, etc.  
They have "on piece" titles (from the 245) but link to the BIBFRAME
Work dataset for the "uniform" titles and the subject and other RDA
work or expression information."

The ISBN question is not addressed.  Will there be space for alternate
ISBNs (e.g. different bindings, simultaneous publishers), and analytic
ISBNs (e,g, individual volumes of a serial or set, accompanying
material such as a CD-ROM, parts of a kit)?  Having a field for
analytic ISBNs (021) was a strength of Utlas, a weakness of MARC.

   __       __   J. McRee (Mac) Elrod ([log in to unmask])
  {__  |   /     Special Libraries Cataloguing   HTTP://
  ___} |__ \__________________________________________________________