MARC 21 Formats

Guidelines for the Use of Field 856

Revised March 2003

Network Development and MARC Standards Office
Library of Congress

March 2003 Revision. This document gives guidelines on the use of field 856 and is current as of March 2003. It includes all changes made to the field through the midwinter ALA conference held in January 2003. It supersedes the August 1999 edition of the guidelines.

A description of the full field is available in the MARC 21 Concise Format for Bibliographic Data, field 856 or in the full format, MARC 21 Format for Bibliographic Data, available from LC's Cataloging Distribution Service (CDS). It is also available in the MARC 21 authority, holdings, classification and community information format documentation.



Field 856 in the MARC 21 bibliographic, holdings, authority, classification, and community information formats is used for electronic location and access information to an electronic resource.

The field may be used in a bibliographic or holdings record for a resource when it or a subset of it is available electronically. In addition, it may be used to locate and access an electronic version of a non-electronic resource described in either the bibliographic record, a portion of the resource described, or a related electronic resource. See the Field 856 in Other Formats section for information about how field 856 is used in the authority, classification, and community information formats.

Field 856 contains the following elements:

Field 856 - Electronic Location and Access (R)

First Indicator
Access method
No information provided
Remote login (Telnet)
Method specified in subfield $2

Second Indicator
No information provided
Version of resource
Related resource
No display constant generated

Subfield Codes
Host name (R)
Access number (R)
Compression information (R)
Path (R)
Electronic name (R)
Processor of request (NR)
Instruction (R)
Bits per second (NR)
Password (NR)
Logon (NR)
Contact for access assistance (R)
Name of location of host (NR)
Operating system (NR)
Port (NR)
Electronic format type (NR)
Settings (NR)
File size (R)
Terminal emulation (R)
Uniform Resource Identifier (R)
Hours access method available (R)
Record control number (R)
Nonpublic note (R)
$y Link text (R)
Public note (R)
$2 Access method (NR)
$3 Materials specified (NR)
$6 Linkage (NR)
$8 Field link and sequence number (R)

General Information

The data in field 856 may be a Uniform Resource Identifier (URI), which is recorded in subfield $u. The necessary locator information may also be parsed into separate defined subfields. Note that separate subfields for locator data was provided when this field was first established in 1993, but generally, these are seldom used. An access method, or protocol used, is given as a value in the first indicator position (if the access method is email, FTP, remote login (telnet), dial-up, or HTTP) or in subfield $2 (if the access method is anything else). The access method is the first element of a URL. The field may also include a Uniform Resource Name or URN (e.g., a DOI (Digital Object Identifier) or handle).

See below for guidelines on repeatability.

Uniform Resource Identifier. For any access method, a Uniform Resource Identifier (URI) is generally recorded in subfield $u. Separate subfields may be used if it is desirable to display data in a particular way.

The most commonly used data elements in field 856 are as follows:

Required subfields. A URI in subfield $u is required unless electronic location and access information is parsed into separate subfields, in which case no single subfield is required. When using this technique, the subfields used largely depends on the access method indicated in the first indicator or in subfield $2 (if first indicator = 7).

Encoding non-MARC characters. In February 1994, Proposal 93-10 defined additional characters in the MARC character set 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. For systems that have not implemented the spacing underscore and tilde, the following alternative characters may be used:

spacing underscore %5F
spacing tilde %7E
Since these characters are valid ASCII strings, the above method allows for the functionality supported by Z39.50 clients and Web browsers which permit users to click on links to access resources represented by URLs. When the additions to the MARC 21 character set are implemented to support the encoding of the spacing characters, it will be possible to replace all instances of the %xx strings.

Multiple 856 fields. There are many reasons to include multiple 856 fields in records. The following are the most common:

See also under subfield $u for repeatability guidelines.

Field 856 in bibliographic or holdings records. Since field 856 is valid in both bibliographic and holdings records, institutions may favor recording it in the holdings record. It is intended to be an electronic equivalent to field 852 (Location), which contains information used to identify the holding organization and other detailed information required to locate a physical item in a collection. In early 1999, the Network Development and MARC Standards Office elicited opinions on whether it is desirable to use the field in bibliographic or holdings records. Responses received generally favored recording the field in the holdings record where practical. However, for a variety of reasons, such as the wider exchange of bibliographic records, many institutions use the bibliographic record despite the benefits of using holdings records.

The following advantages of using holdings records have been expressed:

In order to move towards this approach in the future, it will be necessary to persuade vendors to make the following changes to their ILS systems:

At this point, it is a local decision whether to use the field in bibliographic or holdings records.

Specific Data Elements

First Indicator (Access Method). The first indicator contains information about the access method to the resource and has values defined for Email, FTP, Remote login (Telnet), Dial-up, and HTTP. Access methods without defined values may contain a first indicator value 7 with the method indicated in subfield $2. Older records may contain value 7 and subfield $2 (with content http) if created before value 4 (HTTP) was defined.

The list of indicator values and the values used in subfield $2 is specified in the URL standard (RFC1738) and maintained by the Internet Assigned Numbers Authority (IANA). A list of URI schemes is online at:

For those access methods that have an indicator value defined (ftp, telnet, electronic mail), the URI is included in subfield $u with the appropriate indicator value recorded, even though it is redundant with the first element of the URI.

Value # (blank) (No information provided) may be used if only a URN is recorded in subfield $u. If using a URI in subfield $u with one of the access methods that has a value defined in the first indicator, the access method may be repeated in subfield $2, if desired (e.g., 856 0# $ $2mailto).

Value 7 and subfield $2 is used for electronic access to host-specific file names (i.e., files stored locally) with the access method, "file." This designation is also a defined URL scheme.

Second indicator (Relationship). A second indicator is provided to show the relationship between the information in field 856 and the resource described in the record. This may be used for the generation of a display constant or for ordering multiple 856 fields. For further information, see Proposal No. 97-1 (Definition of Second Indicator (Relationship to Source) in Field 856 of the MARC Formats). Suggested display constants for the indicator values are:

# (blank) Electronic resource:
0 Electronic resource:
1 Electronic version:
2 Related electronic resource:
8 [no display constant generated]

Subfield $3 (Materials specified). Subfield $3 is used to specify to what portion or aspect of the resource the electronic location and access information applies. Specific situations may be:

Subfield $q (Electronic format type).
Subfield $q was originally defined as File transfer mode to include "binary" or "ascii". It was redefined in June 1997 as Electronic format type to accommodate an Internet Media Type (MIME type), such as text/html. Alternatively, textual information about the electronic format type may also be recorded. See under "LC Usage" for a description on how LC has used subfield $q in the American Memory project.

Subfield $u (URI) repeatability. Subfield $u may be repeated only if both a URN and a URL or more than one URN are recorded. Field 856 is repeated if more than one URL needs to be recorded. Some institutions may wish to record a persistent name (URN) as well as a resolvable HTTP URL in field 856.

Example: 856 7#$dsawmp$f1694$u$uurn:hdl:loc.mbrsmi/sawmp.1694$2http

Persistent Uniform Resource Locators (PURLs) at OCLC are intended to deal with the problem of changeable URLs. Functionally, a PURL is a URL, but it is intended to point to an intermediate resolution service. Its persistence depends upon the updating of a PURL database when the location of the resource changes. When recorded in field 856, it is intended to allow for persistence so that each record containing the URL need not be updated when the location changes. Since the PURL is supposed to provide persistent access to the resource, it can be argued that there is no reason to retain a URL that might become invalid. However, this is an internal decision, and institutions that use PURLs should use subfield $x (Nonpublic note) for the original URL if they wish to retain it. This is an appropriate subfield, since it may not be desirable to display the URL to the public because it could cause confusion. The CONSER program has, however, repeated subfield $u to include both the PURL and cooresponding URL in the past.

Subfield $y (Link Text). Subfield $y contains link text which is used for display in place of the URL in subfield $u. Often URLs are difficult to read and most systems do not display them to the user. Since subfield $y was not approved until June 2000 (see Proposal 2000-07), there have been various practices in terms of systems using data in the field as link text. Some systems have used subfields $3 or $z in the past for this purpose. It is not clear how widespread the use of subfield $y is since its approval.

Subfield $z (Public Note). Subfield $z may be used for any additional notes about the electronic resource at the specified location. Examples include subscription information or access restrictions.

Example: $zInclude desired file format following the hyphen in the filename: EID0ASCII, EID-PDF or EID-PS.

Institutions have used subfield $z in various ways. Some have created a note for display repeating the URL in subfield $u. It would be preferable for systems to display subfield $u rather than have those preparing records to include information redundantly.

URIs in Other Fields and Formats

URLs in fields other than field 856. Several proposals resulted in the definition of a subfield $u (URI) in other fields. These fields include:

As with field 856, subfield $u should be repeated only when both a URL and URN is recorded.

Field 856 in other formats. Field 856 is also defined in the authority, classification, and community information formats. It may be used as follows:

LC Usage

Field 856 has been used at the Library of Congress as follows.

Records for resources that have been digitized (or otherwise made available electronically) as part of the National Digital Library Program (American Memory) may contain field 856. Generally, the field is added to the record for the original item, rather than a new record created (unless it consists of components that have been gathered together and only exist as an entity in electronic form). In some cases, LC has also recorded a handle, which is a URN. Older records may contain a URN in subfield $g (which is now obsolete).

LC uses local codes in subfield $q to indicate the different categories of a complex object. This is because digital reproductions created by the Library of Congress are not single files and thus, Internet media types recorded in subfield $q are not applicable. For example, the reproduction of a book usually combines page images and text marked up in SGML. See for a complete list of local codes used in subfield $q.

Example: 856 41$dllst$f072$u$qs

Major Changes Included

The following are major changes made to the August 1999 revision to create these (March 2003 revision) guidelines.


* System supplied element
# Blank
subfield $ Subfield code delimiter

Record #1: 856 link to a subset of the bibliographic item; HTTP URL

Leader *****nam##*******#a
001 2521854
005 19950215082838.3
008 950215s1994####enk######b#####||||#eng##
040 ##$aDLC $cDLC $dDLC
050 00$aHA29$b.A5828 1993
082 00$a300/.1/5195 $220
245 00 $aAnalyzing qualitative data /$cedited by Alan Bryman and Robert G. Burgess.
260 ##$aLondon ;$aNew York :$bRoutledge,$c1994.
300 ##$axii, 232 p. :$bill. ;$c24 cm.
504 ##$aIncludes bibliographical references and index.
020 ##$a0415060621
020 ##$a041506063X (pbk.)
650 #0$aSocial sciences $xStatistical methods.
650 #0$aSocial sciences $xResearch $xMethodology.
700 10$aBryman, Alan.
700 10$aBurgess, Robert G.
856 4#$3Table of contents $u

Record #2: 856 link to item itself; HTTP URL

Leader *****cem##*******#a
001 12934340
005 20021112155042.0
007 cr |||||||||||
008 020918m19999999dcu#a#####|#####|###eng##
010 ##$a 2002627178
034 0#$aa
040 ##$aDLC$cDLC$dDLC
072 #7$aA25$2lcg
110 2#$aLibrary of Congress.$bGeography and Map Division.
245 10$aAmerican Memory map collections: 1500-2002$h[electronic resource].
246 30$aMap collections: 1500-2002
246 1#$iTitle from HTML header:$aMap collections home page
255 ##$aScale not given.
256 ##$aElectronic data and program.
260 ##$a[Washington, D.C.] :$bLibrary of Congress,$c[1999-
538 ##$aMode of access: World Wide Web.
500 ##$aTitle from home page (viewed 9-18-02).
500 ##$aPage last updated June 21, 2002.
520 ##$aThe Geography and Map Division of the Library of Congress offers access to its online map collection for the years 1500-2002. The collection is organized according to seven major categories. Information about the date of
publication, subject, medium, call number, and location of each map is provided.
505 0#$aCities and towns -- Conservation and environment -- Discovery and exploration -- Cultural landscapes -- Military battles and campaigns -- Transportation and communication -- General maps.
651 #0$aUnited States$vMaps.
650 #0$aWorld maps.
650 #0$aMap collections.
610 20$aLibrary of Congress.$bGeography and Map Division$vMaps.
653 ##$aInternet resource--Maps
710 2#$aLibrary of Congress.$bNational Digital Library Program.
856 40$u

Record #3: 856 with Second Indicator Value 2 for Related electronic resource. This record describes the original manuscript collection; 856 field describes the finding aid for the electronic version of that original.

Leader *****npc##*******#e
001 mm78052522
008 780918||||||||||||#################eng##
010 ##$amm 78052522 $bms 69002041
040 ##$aDLC$cDLC
072 #7$aL$2lcmd
100 #1$aJackson, Shirley,$d1919-1965.
245 00$kPapers,$f1932-1970$g(bulk 1932-1965)
300 ##$a7,400$fitems.
300 ##$a51$fcontainers.
300 ##$a20.4$flinear feet.
520 #8$aCorrespondence; diaries; journals; mss., typescripts, and galleys of articles, books, and short stories; college notebooks; watercolors; pencil and ink drawings; and other papers pertaining primarily to Jackson's writings. Includes mss., notes, and outlines relating chiefly to the development of Jackson's short stories through which she conveyed her perception of psychological horror lying just beneath the surface of modern life, as well as to her supernatural tales and to her humorous stories of contemporary domestic life. Correspondents include Jackson's husband, Stanley Edgar Hyman, her parents, Leslie H. and Geraldine B. Jackson, Walter Bernstein, Jean Brockway, Elizabeth Batterham ("Libby") Burke, John Ciardi, Pascal Covici, Carol Black Livaudais, June Mirken Mintz, Frank Orenstein, Louis L. Scher, Mary Shaw, Robert M. Strauss, Louis Untermeyer, Jay Williams, the publishing firm of Farrar, Straus and Young, and Jackson's literary agents Brandt & Brandt and the Music Corporation of America.
541 ##$cGift,$aStanley Edgar Hyman,$d1967.
541 ##$cTransfer,$aStanley Edgar Hyman papers,$bLibrary of Congress Manuscript Division,$d1979.
541 ##$cGift,$aVirginia M. Olsen,$d1991.
544 ##$3Audiotape$etransferred to$aLibrary of Congress Motion Picture, Broadcasting, and Recorded Sound Division.
544 ##$3Selected artifacts$etransferred to$aSmithsonian Institution.
545 ##$aAuthor.
555 8#$aFinding aid available in the Library and on Internet.
600 10$aBernstein, Walter.
600 10$aBrockway, Jean.
600 10$aBurke, Elizabeth Batterham.
600 10$aCiardi, John,$d1916-
600 10$aCovici, Pascal,$d1930-
600 10$aHyman, Stanley Edgar,$d1919-1970.
600 10$aJackson, Geraldine B.
600 10$aJackson, Leslie H.
600 10$aLivaudais, Carol Black.
600 10$aMintz, June Mirken.
600 10$aOrenstein, Frank.
600 10$aScher, Louis L.
600 10$aShaw, Mary.
600 10$aStrauss, Robert M.
600 10$aUntermeyer, Louis,$d1885-1977.
600 10$aWilliams, Jay,$d1914-
610 20$aBrandt & Brandt.
610 20$aFarrar, Straus and Young.
610 20$aMusic Corporation of America.
650 #0$aAmerican fiction.
650 #0$aHorror tales, American.
650 #0$aHumorous stories, American.
650 #0$aShort stories, American.
650 #0$aSupernatural in literature.
656 #7$aAuthors.$2itoamc
852 ##$aLibrary of Congress$bManuscript Division$eWashington, D.C.
856 42$3Finding aid$u

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