| First Indicator | Second Indicator |
|---|---|
| Access method # - No information provided 0 - Email 1 - FTP 2 - Remote login (Telnet) 3 - Dial-up 4 - HTTP 7 - Method specified in subfield $2 |
Relationship # - No information provided 0 - Resource 1 - Version of resource 2 - Related resource 3 - Component part(s) of resource 4 - Version of component part(s) of resource 8 - No display constant generated |
| Subfield Codes | |
|---|---|
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Information needed to locate and access electronic information. The field may be used in an authority record to provide supplementary information available electronically about the entity for which the record was created. The phrase "networked electronic resource" is used to refer to an electronic resource for which content is accessed using a network protocol like telnet, http, ftp, etc.
Field 856 is repeated when the location data elements vary (the URL in subfield $u or subfields $a and $d, when used). It is also repeated when more than one access method is used, mirror sites are recorded, different formats/resolutions with different URLs are indicated, and related items are recorded.
First Indicator - Access method
Value that defines the access method to the electronic resource. If the resource is available by more than one access method, the field is repeated with data appropriate to each method. When recording a URL in subfield $u, the value corresponds to the access method (URL scheme), which is also the first element in the URL string.
Methods defined are the main TCP/IP (Transmission Control Protocol/Internet Protocol) protocols.
Access to the electronic resource is through electronic mail (email). Access includes subscribing to an electronic journal or electronic forum through software intended to be used by an email system.
Access to the electronic resource is through the File Transfer Protocol (FTP).
Access to the electronic resource is through remote login (Telnet).
Access to the electronic resource is through a conventional telephone line (dial-up). Additional information in subfields of the record may enable the user to connect to the resource.
Access to the electronic resource is through the Hypertext Transfer Protocol (HTTP).
Access to the electronic resource is through a method other than the defined values and for which an identifying code is given in subfield $2 (Source of access).
Second Indicator - Relationship
Relationship between a networked electronic resource at the location identified in field 856 and the resource described in the record as a whole.
Only value # (No information provided) is used for authority records.
Do not apply these indicator values to authority records.
$a - Host name
Fully qualified domain (host name) of the electronic location. It contains a network address which is repeated if there is more than one address for the same host.
$c - Compression information
Information about the compression of a file, in particular, whether a specific program is required to decompress the file.
May be repeated if two compression programs are used, noting the latest compression first.
$d - Path
Path is the series of logical directory and subdirectory names that indicate where a file is stored. The filename itself is recorded in subfield $f. This may be a surrogate path leading the user to the host where complete and current access information is stored in a locator table.
$e - Data provenance
See description of this subfield in Appendix H: Data Provenance Subfields.
$f - Electronic name
Electronic name of a file as it exists in the directory/subdirectory indicated in subfield $d on the host identified in subfield $a. Subfield $f may be repeated if a single logical file has been divided into parts and stored under different names. In this case, the separate parts should constitute a single bibliographic item. In all other cases, a file that may be retrieved under different filenames contains multiple occurrences of field 856, each with its corresponding electronic name in subfield $f. A filename may include wildcard characters (e.g., * or ?) if applicable. Use subfield $z to explain how files are named, if needed.
$g - Persistent identifier
Persistent identifier (PID) assigned to the resource for automated access and other resolution services by a PID resolver. PIDs should be provided as actionable hyperlinks (e.g., HTTP URI format).
If a PID resolves to more than one URI, these URIs may be provided in the same 856 field, with repeated subfield $u.
$h - Non-functioning Uniform Resource Identifier
Uniform Resource Identifier (URI), which is no longer functional, for example, due to link rot, content drift, etc.
Subfield $h may be repeated if there is more than one non-functioning URI. A note on the status change (including the date) may be added in either in subfield $x or subfield $z, depending on the local policy.
$l - Standardized information governing access
The subfield contains standardized information about the access status of a resource. The information may be in the form of a value from a controlled vocabulary, or a Uniform Resource Identifier (URI). If the information is a value from a controlled vocabulary, it is preceded by the appropriate value from the list of Access Restriction Term Source Codes, enclosed in parentheses. When the information is given in the form of a Web retrieval protocol, e.g., HTTP URI, no preceding parenthetical is used.
$m - Contact for access assistance
Name of a contact for assistance in accessing a resource at the host specified in subfield $a. For addresses relating to the content of the resource itself (i.e. the item represented by the title recorded in field 245) rather than access assistance, field 270 is used. If the address data is the same, use field 270.
$n - Terms governing access
The subfield contains textual information about the access status of a resource.
$o - Operating system
For informational purposes, the operating system used by the host specified in subfield $a may be indicated here. Conventions for the path and filenames may be dependent on the operating system of the host. For the operating system of the resource itself (i.e., the item represented by the title recorded in field 245), rather than the operating system of the host making it available, field 753 (Technical Details Access to Computer Files), subfield $c (Operating system) is used.
$p - Port
Portion of the address that identifies a process or service in the host.
$q - Electronic format type
Identification of the electronic format type and version. Electronic format type should be specified with a code from the list of registered Internet Media Types (MIME types), taken from: IANA Media Types. If necessary (e.g., in order to specify a file format version to support access or digital preservation) additional information, such as PRONOM Unique Identifier (PUID) codes, may be included in addition to the information provided by the MIME Type by repeating subfield $q.
$r - Standardized information governing use and reproduction
The subfield contains standardized information about the use and reproduction rights of a resource. The information may be in the form of a value from a controlled vocabulary, or a Uniform Resource Identifier (URI). If the information is a value from a controlled vocabulary, it is preceded by the appropriate value from the list of Access Restriction Term Source Codes, enclosed in parentheses. When the information is given in the form of a Web retrieval protocol, e.g., HTTP URI, no preceding parenthetical is used.
$s - File size
Size of the file as stored under the filename indicated in subfield $f. It is generally expressed in terms of 8-bit bytes (octets). It may be repeated in cases where the filename is repeated and directly follows the subfield $f to which it applies. This information is not given for journals, since field 856 relates to the entire title, not to particular issues.
$t - Terms governing use and reproduction
The subfield contains textual information about the use and reproduction rights of a resource.
$u - Uniform Resource Identifier
Uniform Resource Identifier (URI), which provides standard syntax for locating an object using existing Internet protocols or by resolution of a persistent identifier (PID). Field 856 is structured to allow for the creation of a URL from the concatenation of other separate 856 subfields. Subfield $u may be used instead of those separate subfields or in addition to them.
Subfield $u may be repeated if more than one URI is recorded.
URIs which no longer function to provide access to the described resource may be transferred to 856 $h.
$v - Hours access method available
Hours that access to an electronic resource is available at the location indicated in this field. Only used to record hours of availability of the specific location indicated in field 856.
$w - Record control number
System control number of the related record preceded by the MARC code, enclosed in parentheses, for the agency to which the control number applies. The data in the subfield links field 856 to the MARC record having the same data in a control number field. See Appendix G for a listing of organization code sources used in MARC 21 records.
$x - Nonpublic note
Note relating to the electronic location of the source identified in the field. The note is written in a form that is not adequate or intended for public display. It may also contain processing information about the file at the location specified.
$y - Link text
Link text is used for display in place of the URL in subfield $u (Uniform resource identifier). When subfield $y is present, applications should use the contents of it as the link instead of subfield $u linking to the destination in subfield $u.
Use of the link text is independent of any decision concerning the second indicator value.
$z - Public note
Note relating to the electronic location of the source identified in the field. The note is written in a form that is adequate or intended for public display.
$2 - Access method
Access method when the first indicator position contains value 7 (Method specified in subfield $2). Code from: Electronic Access Methods Code List.
$3 - Materials specified
Information that specifies the part of the entity to which the field applies.
$6 - Linkage
See description of this subfield in Appendix A: Control Subfields.
$7 - Access status
Code indicating the availability of access to the networked electronic resource the address of which appears in subfield $g and/or subfield $u. Subfield $7 applies to all subfields $g and $u present in the field. If a persistent identifier in subfield $g has a different access status from a URI in subfield $u, repeat the field in order to include both URIs.
The networked electronic resource is freely and openly accessible online to everyone, without restriction, login, or payment.
The networked electronic resource is not freely and openly accessible online.
$8 - Field link and sequence number
See description of this subfield in Appendix A: Control Subfields.
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856 with URL/URN:
|
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| 100 | 1#$aRussell,Bertrand,$d1872-1970 | ||||||||
| 856 | 4#$uhttp://plato.stanford.edu/entries/russell/russell.jpeg$yphotograph | ||||||||
| 100 | 0#$aLeonardo,$cda Vinci,$d1452-1519.$tMona Lisa | ||||||||
| 856 | 4#$uhttp://www.ibiblio.org/wm/paint/auth/vinci/joconde/$ydescription | ||||||||
| 856 | 4#$3image$uhttp://www.ibiblio.org/wm/paint/auth/vinci/joconde/joconde.jpg | ||||||||
| 110 | 2#$aLibrary of Congress.$bCopyright Office | ||||||||
| 856 | 4#$u//aj.sunback.homes/copyright | ||||||||
| 111 | 2#$aInternational Conference on the Principles and Future Development of AACR | ||||||||
| 856 | 4#$uhttp://www.collectionscanada.ca/jsc/ | ||||||||
| 150 | ##$aPresidents’ spouses$zUnited States | ||||||||
| 856 | 4#$uhttp://www.firstladies.org/ | ||||||||
Spacing underscore and tilde in URLs - In February 1994, additional characters in the MARC character set were defined to both accommodate existing bibliographic needs and to align it with the ASCII and ANSEL character sets. Both the spacing underscore and the spacing tilde were added at the time because of the need in directory and file names for electronic resources.
Many systems have implemented these characters, however, for systems that have not implemented the spacing underscore and tilde, the following alternative characters may be used:
| %5F for spacing underscore |
| %7E for spacing tilde |
In 2022 Indicator 2 and its values were updated to reflect contemporary usage, clarify the defined relationships, allow for identification of component parts, and support access to online resources in an environment dominated by web resources.
Because subfield $g (Electronic name - End of range) was rarely if ever used, it was redefined as Uniform Resource Name in 1997. It was subsequently made obsolete in favor of recording the URN in subfield $u.
Subfield $q was made repeatable and was redescribed in order to more accurately specify electronic file formats and their versions.
Prior to 1999, subfield $u was defined as repeatable. It was changed to not repeatable in favor of repeating the field due to ambiguity in determining when the subfield could be repeatable. Subfield $u was changed back to repeatable and renamed in 2000 to record URNs after subfield $g was made obsolete.
The definition of subfield $u was broadened in order to accommodate the recording of persistent identifiers (PIDs) and multiple URLs in a single 856 field.
The definition of subfield $7 was broadened in order to specify access status information for URIs identified in subfield $g in addition to subfield $u.