Control number assigned by the organization creating, using, or distributing the record.
For interchange purposes, documentation of the structure of the control number and input conventions should be provided to exchange partners by the organization initiating the interchange. The MARC code identifying whose system control number is present in field 001 is contained in field 003 (Control Number Identifier). An organization using a record of another organization may move the incoming control number from field 001 (and the control number identifier from field 003) to field 035 (System Control Number), 010 (Library of Congress Control Number), or 016 (National Bibliographic Agency Control Number), as appropriate, and place its own system control number in field 001 (and its control number identifier in field 003).
[LC generally supplies its control number in both fields 001 and 010]