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DATE: May 23, 2024
REVISED:
NAME: Adding Subfields $0 and $1 to Fields 506 and 540 in the MARC 21 Bibliographic Format
SOURCE: PCC Standing Committee on Standards, PCC Standing Committee on Applications
SUMMARY: This proposal adds subfields $0 (Authority record control number or standard number) and $1 (Real World Object URI) to fields 506 (Restrictions on Access Note) and 540 (Terms Governing Use and Reproduction Note) in the MARC 21 Bibliographic Format.
KEYWORDS: Field 506 (BD); Restrictions on Access Note (BD); Field 540 (BD); Terms Governing Use and Reproduction Note (BD); Subfield $0, in field 506 (BD); Subfield $0, in field 540 (BD); Subfield $1, in field 506 (BD); Subfield $1, in field 540 (BD); Subfield $u, in field 506 (BD); Subfield $u, in field 540 (BD); Authority record control number or standard number (BD); Real World Object URI (BD); Uniform Resource Identifier (BD)
RELATED: 2024-DP04; 2020-FT02; 2020-FT03; 2021-04; 2023-FT01; 2017-06; 2017-08; 2002-10
STATUS/COMMENTS:
05/23/24 – Made available to the MARC community for discussion.
06/25/24 – Results of MARC Advisory Committee discussion: Approved, with the amendment to change the name of field 540 subfield $f (Use and reproduction rights) to "Standardized terminology for use and reproduction rights" in order to better align with the name of field 506 subfield $f (Standardized terminology for access restriction).
10/31/24 – Results of MARC Steering Group review - Agreed with the MAC decision.
05/08/25 – Amendment to proposal - Because of an oversight in the proposal, changes to field 540 were not extended to field 845 (Terms Governing Use and Reproduction Note) in the MARC 21 Holdings Format. Holdings field 845 (https://aj.sunback.homes/marc/holdings/hd845.html) was expressly defined to be identical to Bibliographic field 540. The MARC Steering Group thus approved that the proposed changes in the paper be extended to Holdings field 845 as part of the MARC Update No. 40 process, thereby keeping the two fields identical.
Over the course of multiple proposals, subfields $0 (Authority record control number or standard number) and $1 (Real World Object URI) have been added to numerous fields in the MARC Bibliographic and Authority Formats to enhance linked data compatibility in MARC. In 2022, the Program for Cooperative Cataloging (PCC) Standing Committee on Applications (SCA) charged a task group to review and identify additional descriptive practices and MARC fields that could benefit from linked data vocabularies, and to propose strategies to implement those improvements. The group reviewed descriptive (non-access) MARC fields in which subfields $0 and $1 were not already defined, and ultimately recommended the definition of these subfields in several fields in the Bibliographic Format. The PCC Policy Committee (PoCo) approved a majority of the task group's recommendations in 2023 and thereafter charged the PCC Standing Committee on Standards (SCS) to implement the approved recommendations. This proposal represents one element of this work, and pursues the definition of subfields $0 and $1 in fields 506 and 540, with a goal of enabling linked data enhancements in those fields. Due to a number of similarities between fields 506 and 540, this proposal combines the two recommendations. The other approved recommendations of the SCA task group requiring MARC revisions are being pursued in separate papers.
This proposal seeks to define subfields $0 and $1 in field 506 (Restrictions on Access Note). The identifier or URI contained in subfield $0 or $1 corresponds to a standard term contained in subfield $f of field 506, taken from the vocabulary specified in subfield $2. The identifier does not relate to values in subfield $b (Jurisdiction) or to data in another subfield besides subfield $f. Subfield $2 is coded from the Access Restriction Term Source Codes list. Two of these sources have URIs available: the COAR Access Rights Vocabulary and Wikidata.
During review of the task group's recommendations, it was also suggested that it may be redundant to define subfields $0 and $1 in field 506 when the existing subfield $l (Standardized information governing access) in field 856 can be used to more directly link an identifier for the access status to the URL for the resource in subfield $u, to which the restriction status applies. In response, the authors of this paper note that field 506 is also used to indicate access restrictions for non-electronic resources, such as archival collections, which may not have an 856 field for electronic access. Or, a bibliographic record for an archival collection may contain an 856 field for a related resource such as a finding aid, which may have different access parameters than the collection itself. This suggests that new subfields $0 and $1 in field 506 are not necessarily redundant with the existing subfields in field 856, as a record could contain meaningfully different access statuses and corresponding URIs in fields 506 and 856.
This proposal seeks to define subfields $0 and $1 in field 540 (Terms Governing Use and Reproduction Note). As with field 506, subfield $2 is coded from the Access Restriction Term Source Codes list. The identifier contained in subfield $0 or $1 corresponds to a standard term from one of these vocabularies contained in subfield $f of field 540. The identifier does not relate to information in subfield $b (Jurisdiction) or to data in another subfield besides subfield $f. A source code was approved for Wikidata, and URIs could also be assigned from Rights Statements. As will be discussed in section 2.4, URIs may exist in other sources that lack a source code established in the list; for example, the Copyright Status vocabulary found on id.loc.gov does not currently have a source code.
Also, there is an existing subfield $r (Standardized information governing use and reproduction) in field 856 which can contain identifiers related to terms governing use and reproduction of an electronic resource. Again, field 540 is also used in bibliographic records for non-electronic resources, such as archival collections, for which an 856 field for the resource may not be applicable. This suggests a distinct use for subfields $0 and $1 in 540, whether or not an 856 field with a URI in subfield $r is also present in the same record.
Based on feedback received from discussion of 2024-DP04 prior to and during the MAC Midwinter 2024 meeting, additional clarification is needed to distinguish between the newly proposed subfields and the existing subfield $u (Uniform Resource Identifier), as defined in fields 506 and 540 among other fields. Subfield $0 could potentially contain control numbers or standard numbers that are not machine actionable URIs. Meanwhile, subfield $u could contain URLs that do not serve as identifiers for the access or rights status itself as a concept or term. Such URLs could include links to patron registration forms, websites containing institutional access or user policies, etc., as shown in some examples below.
Subfield $u was added to fields 506 and 540 in MARBI Proposal 2002-10, "to provide a direct link between bibliographic records and addressable electronic files containing current information concerning restrictions imposed on access, use and/or reproduction of materials described in the records." Examples and further discussion indicate that "URI subfields have been defined when records can be enhanced by making an outside link to a web resource that includes data appropriate to a defined MARC field. Reasons for defining subfield $u in additional fields have included the fact that it facilitates maintaining current information (it is more efficient to update the linked data than numerous bibliographic records). In addition, subfield $u helps control the size of record; repetitious, often lengthy data can be placed elsewhere."
Possibly, this distinction between subfields $0/$1 and $u could be further clarified by renaming subfield $u, for example from Uniform Resource Identifier to Uniform Resource Locator, or updating the subfield definition of $u to better distinguish it from the types of URIs recorded in subfields $0 or $1. Though it is beyond the scope of this proposal, MAC might consider making the same editorial change in other fields in the 5XX block of the Bibliographic Format, for which subfield $u is defined as Uniform Resource Identifier (including 510, 514, 520, 530, 542, 545, 552, 555, 561, and 583), and elsewhere in the MARC formats, especially where subfields $0 or $1 are also present alongside $u in the same field. Alternatively, external guidance and best practices can clarify the difference. For example, the PCC Task Group on URIs in MARC provided this guidance in an FAQ document: "These subfields should not be confused with $u (Uniform Resource Identifier), which should only be used to record document web addresses or URLs."
Feedback on 2024-DP04 also asked for clarity around repeatability and independent use of $0 and $1 shown in some examples in that paper. Subfields $0 and $1 are typically defined as repeatable across the MARC formats (Authority field 024 being one exception). We therefore propose defining them as repeatable in fields 506 and 504. However as a matter of community-defined best practice, we anticipate the application of repeated $0 or $1 in the same field to be uncommon in reality. The PCC's FAQ document again states: "Strictly speaking the MARC definitions place no constraints on the number of URIs or their source. But using URIs from different sources creates conceptual and practical problems it would be best to avoid. Generally, only one $0 and/or one $1 should be provided." If multiple terms from the same vocabulary are repeated in separate instances of subfield $f, and associated identifiers in $0 or $1 are also being recorded, it will likely be preferable to instead use separate instances of the field, each one containing a controlled term in a single instance of subfield $f and its corresponding identifiers in $0 or $1. Possibly, repeated $0 or $1 could exist in cases when subfields $f and $2 are not also being used in the same field, as will be discussed next.
Some examples contained in 2024-DP04 demonstrated use of subfields $0 and $1 without a corresponding controlled term in subfield $f. Discussion of the paper prior to and during the MAC Midwinter 2024 meeting questioned whether this was intentional. We believe it is possible that useful identifiers exist from sources that do not have an established controlled vocabulary source available for use in the same field. Additionally, repeatability of subfields $0 and $1 may make more sense if subfields $f and $2 are not present in the same field; when there is not a declared source for a controlled term, identifiers for the same concept could potentially come from multiple sources.
The examples showed use of URIs from two applicable vocabularies that currently lack source codes: the Preservation Copyright Status vocabulary from id.loc.gov, and the Traditional Knowledge Labels and Biocultural Labels from Local Contexts. One such omitted example was given as follows:
540 ## $a This work has entered the public domain. $0 http://id.loc.gov/vocabulary/preservation/copyrightStatus/pub
We have nonetheless omitted or revised this and other examples showing the possibility of using subfields $0 or $1 without subfield $f. We have also updated the definition of subfield $0 to associate it more explicitly with subfield $f. In doing so, we note that such definitions are uncommon in other MARC fields in which subfields $0 or $1 are defined. In most cases, these subfields are defined merely with a reference to Appendix A: Control Subfields. By exception, the definition of subfield $0 in MARC Bibliographic field 023 associates subfield $0 with the controlled value contained in subfield $a, and the definition of subfield $0 in the interrelated fields 033 and 518 associate subfield $0 with the controlled place term contained in subfield $p. The definition of subfield $1 does not similarly associate the RWO URI with a value contained in another subfield, in fields 023, 033, 518, or elsewhere. The PCC MARC URI Task Group FAQ document states regarding the difference between subfields $0 and $1: "...there is no special dependency between $1 and other subfields in the same field. In particular, $1 is not defined as a source for an authority controlled heading." Therefore, this proposal does not seek to introduce new dependencies or constraints on subfield $1 that would apply in only these two fields.
Source codes may be proposed for the other vocabulary sources discussed above, so that identifiers and URIs may be associated with a controlled term from those sources when needed. But there remains a broader question beyond fields 506 and 540 alone: can an identifier or URI be recorded in a subfield $0 or $1 alone, without a corresponding label or controlled value recorded in the same field? This may include cases where the desired vocabulary does not yet have a source code. It is also theoretically possible that a controlled term from an unestablished source could be recorded in the appropriate subfield but without a code in subfield $2 specifying the source of that term. This could be done whether or not the field also contains a corresponding identifier in subfields $0 or $1. In the case of fields 506 and 540, attempting to record a subfield $f without a corresponding subfield $2 currently causes a validation error in OCLC Connexion, so system validation tables would need to be updated to allow subfield $f when subfield $2 is absent as in this hypothetical example:
540 ## $a This work has entered the public domain. $f public domain $0 http://id.loc.gov/vocabulary/preservation/copyrightStatus/pub
Or, as explored in Proposal 2023-03, concepts from some sources (like Wikidata) may not have a stable or unique preferred label to record in subfield $f. That proposal suggested that "in one possible implementation scenario, $0 or $1 could be given without an accompanying label in $a; a suitable label could subsequently be pulled in and populated either into the source MARC record or into the discovery layer to serve the needs of a particular audience." Though that proposal was implemented, MARC Bibliographic Format Appendix A: Control Subfields and specific field documentation does not seem to specifically address this possible implementation of subfields $0 or $1. Authority field 024 is again an exception in this regard; its documentation states that "indicating source of a URI in $0 or $1 is optional when there is no $a." This suggests that in at least some cases, subfields $0 or $1 can be recorded independently of an associated value in the same field (in that case a standard number or code in subfield $a), though there are no examples of this provided. No other examples have been found elsewhere in the MARC Formats showing a subfield $0 or $1 without an associated value in another subfield of the same field. Authority field 024 suggests that the use of subfields $0 or $1 alone is not wholly forbidden in the MARC Formats, and the PCC FAQ mentioned above asserts that subfield $1 in particular should have no specific dependency on another subfield. While we are not attempting to resolve this question here, this suggests a need for further clarification, possibly in MARC Appendix A, or in additional community best practice documentation for the use of these subfields.
The Standing Committee on Standards has considered different ways to ensure reliable machine actionability of information contained in field 506, and to a lesser extent 540. In particular, the ExLibris Alma ILS system currently uses standardized information in subfields $f and $2 in field 506 to generate an "Open Access" indicator for open access resources in public displays. Other systems rely on first indicator values in field 506, or numerical codes in subfield $7 of field 856, to provide similar machine actionability. Subfields $0 and $1 would provide other options for both linked data enhancement and machine actionability related to access and rights status, such as displaying icons or multilingual labels related to the status, faceting searches based on status, and restricting access based on status.
During the initial review of 2024-DP04, it was noted that it was unusual to have subfields $0 or $1 in a note field (Bibliographic 5XX field block). At the time of writing, the only exceptions are 518 (Date/Time and Place of an Event Note) and 567 (Methodology Note). Subfields $0 and $1 were established in these fields in Proposals 2017-08 and 2017-06. As already mentioned, in field 518, subfield $0 is defined specifically as the control number of the record for a controlled place term in subfield $p (Place of event), but subfield $1 is not specifically tied to subfield $p. In field 567, $0 and $1 are also only generically defined with a reference to Appendix A, but it may be inferred that they relate to a controlled term for the methodology in subfield $b (Controlled term), taken from a vocabulary specified in $2.
We believe that the use case for subfields $0 and $1 is the most straightforward in note fields in which subfield $2 already exists, as is the case with fields 506 and 540. In these fields, a term in subfield $f can already be associated with a controlled vocabulary or code. The definition of subfields $0 and $1 would build on the control provided by associating a term with a source in subfield $2, such as term maintenance, mapping, translation, and faceting. Other note fields that contain structured or standardized data points could also be candidates for similar linked data enhancement and machine actionability through the establishment of new control subfields, including subfields $0, $1 and $2. The SCA task group also recommended adding subfields $0 and $1 to field 586 (Awards note), which SCS will consider in a separate paper. As other possible examples, the names of universities or departments contained in Bibliographic field 502 (Dissertation note) or the standardized citation forms of bibliographic sources in Bibliographic field 510 could be controlled in a similar fashion. Alternatively, potentially controllable elements of note fields in the 5XX block have been instead accommodated in other fields. For example, a controlled term for a form of musical notation is recorded in subfield $c of field 348 instead of subfield $b of field 546, and accordingly, identifiers are also accommodated in subfields $0 and $1 of field 348 instead of in field 546.
Between fields 506, 540, and various subfields in 856, there are already several recording options to convey access and rights statuses, including indicator values, codes, free-text notes, and controlled terms. If approved, the ability to record standard identifiers and RWO URIs will increase the number of options. This aligns somewhat with RDA's four recording method options (structured description, unstructured description, identifier, and IRI). Community best practice and system needs may dictate which method or methods are preferred and how they may or may not be combined or repeated.
Lastly, we note that a separate discussion paper, 2024-DP08, seeks to define subfield $7 (Data provenance) in fields 506 and 540.
In field 506 (Restrictions on Access Note) of the MARC 21 Bibliographic Format, define the following new subfields:
$0 - Authority record control number or standard number (R)
Control number or standard number for a controlled term in subfield $f.
See description of this subfield in Appendix A: Control Subfields.$1 - Real World Object URI (R)
See description of this subfield in Appendix A: Control Subfields.
In field 540 (Terms Governing Use and Reproduction Note) of the MARC 21 Bibliographic Format, define the following new subfields:
$0 - Authority record control number or standard number (R)
Control number or standard number for a controlled term in subfield $f.
See description of this subfield in Appendix A: Control Subfields.$1 - Real World Object URI (R)
See description of this subfield in Appendix A: Control Subfields.
Example 1:
506 1# $a Access restricted to authorized researchers $f restricted access $2 coarar $0 http://purl.org/coar/access_right/c_16ec
Example 2:
506 1# $a Access restricted; materials have been deemed culturally sensitive. See the Statement of intent regarding culturally sensitive items in our collections here:
$u https://wellcomecollection.org/pages/YJkM-REAACMABEhW $f restricted access $2 coarar $0 http://purl.org/coar/access_right/c_16ec
Example 3:
506 1# $a Access restricted to registered users by appointment. Plan your visit and view user policies here: $u https://library.columbia.edu/libraries/rbml/usingcollections.html $f restricted access $2 coarar $0 http://purl.org/coar/access_right/c_16ec
Example 4:
506 0# $a Open access $f open access $2 wikidata $1 http://www.wikidata.org/entity/Q232932
Example 1:
540 ## $f In Copyright - Educational Use Permitted $2 rs $0 http://rightsstatements.org/vocab/InC-EDU/1.0/
Example 2:
540 ## $a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License $f CC BY-NC-ND 4.0 $2 cc $0 https://creativecommons.org/licenses/by-nc-nd/4.0/
Example 3:
540 ## $a Rights status not evaluated. For general information see "Copyright and Other Restrictions..." $u http://lcweb.loc.gov/rr/print/195_copr.html $f Copyright not evaluated $2 rs $0 http://rightsstatements.org/vocab/CNE/1.0/
Example 4:
540 ## $a This work is in the public domain. $f public domain $2 wikidata $1 http://www.wikidata.org/entity/Q19652
The BIBFRAME data conversion programs can accommodate this request. For example:
<bf:usageAndAccessPolicy>
<bf:AccessPolicy rdf:about="http://purl.org/coar/access_right/c_16ec" />
<rdfs:label>restricted access</rdfs:label>
<bf:source rdf:resource="http://id.loc.gov/vocabulary/accessrestrictionterm/coarar" />
</bf:AccessPolicy>
</bf:usageAndAccessPolicy><bf:usageAndAccessPolicy>
<bf:UsePolicy rdf:about="http://rightsstatements.org/vocab/InC-EDU/1.0/" />
<rdfs:label>In Copyright - Educational Use Permitted</rdfs:label>
<bf:source rdf:resource="http://id.loc.gov/vocabulary/accessrestrictionterm/rs">
</bf:UsePolicy>
</bf:usageAndAccessPolicy>
Communities interested in adding these subfields may wish to establish best practices for their usage. The conversion will be cleaner if the controlled vocabulary term in $f and the URI in $0 or $1 are placed in a separate MARC field.
In fields 506 (Restrictions on Access Note) and 540 (Terms Governing Use and Reproduction Note) of the MARC 21 Bibliographic Format, define the following new subfelds:
$0 - Authority record control number or standard number (R)
$1 - Real World Object URI (R)
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