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OCLC Support

Summary of processing changes

Learn about the history of the 049 field, the communication format, and the OCLC number.

 Note: The changes described in this guide have been incorporated into relevant areas of the OCLC support site.  

  • History of field 049
    Find the history of field 049, including its placement in a bibliographic record, indicators, and repeatability.
  • History of the communication format
    Find the history of the communication format from the 1974-2016.
  • History of the OCLC number
    Find a brief description of the various forms of OCLC numbers that OCLC has output in OCLC-MARC via subscription and export from various OCLC cataloging services.