# International Standard Serial Number

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An International Standard Serial Number (ISSN) is a unique eight-digit number used to identify a print or electronic periodical publication. The ISSN system was adopted as international standard ISO 3297 in 1975. The ISO subcommittee TC 46/SC 9 is responsible for the standard. Although International Standard Serial Number identifies periodicals, it does not identify specific volume or articles in each volume. Thus, Serial Item and Contribution Identifier (SICI) was developed as an extension of ISSN. SICI is a recognized international standard used by periodical publishers, bibliographic utilities, and library communities.

Today, numerous periodicals are published both in print and online in various languages. Some journals have similar titles and some have identical titles in different foreign languages. It is nearly impossible to organize, manage, and identify journals and articles without these standardized identification methods. ISSN and SICI are the outcome of international collaboration amongst publishing industries, libraries, and other bibliographic institutions.

## Code format

The format of the ISSN is an eight digit number, divided by a hyphen into two four-digit numbers. The last digit, which may be 0–9 or an X, is a check digit.

A "check digit" is a form of redundancy check used for error detection, the decimal equivalent of a binary checksum. It consists of a single digit computed from the other digits in the message. With a check digit, one can detect simple errors in the input of a series of digits, such as a single mistyped digit, or the permutation of two successive digits.

The ISSN of the journal Hearing Research, for example, is 0378-5955. To confirm the check digit, the following algorithm may be used:

Calculate the sum of the first seven digits of above ISSN multiplied by 8, 7, 6, 5, 4, 3, and 2, respectively:

0*8 + 3*7 + 7*6 + 8*5 + 5*4 + 9*3 + 5*2
= 0 + 21 + 42 + 40 + 20 + 27 + 10
= 160.

The modulus 11 of this sum is then calculated. Some calculators have a mod() function:

160 mod 11 = 6

Alternatively, one can divide the sum by 11 and determine the remainder:

160/11 = 14 remainder 6

This modulus or remainder value is then subtracted from 11 to give the check digit:

11 - 6 = 5
5 is the check digit.

An upper case X in the check digit position indicates a check digit of 10.

## Code assignment

ISSN codes are assigned by a network of ISSN National Centres, usually located at national libraries and coordinated by the ISSN International Centre based in Paris. The International Centre is an intergovernmental organization created in 1974, through an agreement between UNESCO and the French government. The International Centre maintains a database of all ISSNs assigned worldwide, the ISDS Register (International Serials Data System) otherwise known as the ISSN Register. The ISSN Register contains ISSN codes and descriptions for more than one million periodicals[1] with around 50,000 new records added yearly.

## Comparison to other identifiers

ISSN and ISBN codes are similar in concept, where ISBNs are assigned to individual books. For particular issues of a periodical an ISBN might be assigned in addition to the ISSN code for the periodical as a whole. Unlike the ISBN code, an ISSN is an anonymous identifier associated with a periodical title, containing no information as to the publisher or its location. For this reason, a new ISSN is assigned to a periodical each time it undergoes a major title change.

Since the ISSN applies to an entire periodical, a new identifier, the Serial Item and Contribution Identifier (see below), was built on top of it, to allow referencing specific volumes, articles, or other identifiable components.

## Availability

The ISSN Register is not freely available for interrogation on the web but is available on a subscription basis. There are several routes to the identification and verification of ISSN codes for the general public.

• The print version of a periodical typically will include the ISSN code as part of the publication information
• Most, though not all, periodical websites contain ISSN code information
• Derivative lists of publications will often contain ISSN codes; these can be found through on-line searches with the ISSN code itself or periodical title

## Use in URNs

An ISSN can be encoded as a URN (Uniform Resource Name) by prefixing it with "urn:issn:".[2] For example Rail could be referred to as "urn:issn:1534-0481." If the checksum digit is "X" then it is always encoded in uppercase in a URN.

## Serial Item and Contribution Identifier

The Serial Item and Contribution Identifier (SICI) is a code (ANSI/NISO standard Z39.56) used to uniquely identify specific volumes, articles or other identifiable parts of a periodical. It is “intended primarily for use by those members of the bibliographic community involved in the use or management of serial titles and their contributions.”

### Description

It is an extension of the International Standard Serial Number, which identifies an entire periodical (similar to the way an ISBN number identifies a specific book). The ISSN applies to the entire publication, however, including every volume ever printed, so this more specific identifier was developed by the Serials Industry Systems Advisory Committee (SISAC) to allow references to specific parts of a journal.

The variable-length code is compatible with other identifiers, such as DOI, PII, and URN.[3] It is free of charge.

The SICI is a recognized international standard and is in wide use by publishers and the bibliographic community, primarily as an aid to finding existing articles or issues.[4] JSTOR adopted SICIs in 2001 as the primary article identifier, due to their persistence and applicability to the many types of journal content found in JSTOR's archive.[5]

### Details

The SICI code is composed of three segments, intended to be both human-readable and easy for machines to parse automatically. The following example SICI is explained below:[6]

Item
Abstract from Lynch, Clifford A. “The Integrity of Digital Information; Mechanics and Definitional Issues.” JASIS 45:10 (Dec. 1994) p. 737-44
SICI
0002-8231(199412)45:10<737:TIODIM>2.3.TX;2-M

### Item segment

0002-8231
This is the ISSN for the periodical, in this case the Journal of the American Society for Information Science
(199412)
The chronology part is in parentheses and identifies the date of publication. In this case, it is signified by month and year; December 1994
45:10
The enumeration part signifies the volume and number; Vol. 45, no. 10.

#### Contribution segment

<
Signifies the start of the contribution segment
737
Location code: signifies the page number, frame number, reel number, and so on. In this case, page 737
TIODIM
Title code: based on the title of the article. In this case, an initialism: “The Integrity of Digital Information; Mechanics and Definitional Issues.”
>
Signifies the end of the contribution segment

### Control segment

2
Code Structure Identifier (CSI) for the type of SICI being constructed
3
Derivative Part Identifier (DPI) identifies a part of the contribution, such as a table of contents or abstract
TX
Format identifier two-letter code signifying the way content is presented. In this case, TX = printed text
2-
Standard version number
M
Check character allows a computer to detect errors in the code, similar to ISBN's check digit

## Notes

1. ISSN Statistic Homepage, One million milestone.
2. IETF, Using The ISSN (International Serial Standard Number) as URN (Uniform Resource Names) within an ISSN-URN Namespace—RFC 3044. Retrieved October 13, 2008.
3. UKSG, The DOI (Digital Object Identifier). Retrieved October 13, 2008.
4. Ukoln, Evaluation of SICI (Serial Item and Contribution Identifier). Retrieved October 13, 2008.
5. JSTOR, JSTOR and “Deep Linking,” JSTORNEWS. Retrieved October 13, 2008.
6. UKOLN, What is the SICI? Retrieved October 13, 2008.

## ReferencesISBN links support NWE through referral fees

• Alan, Robert. 1993. "Linking Successive Entries Based Upon the OCLC Control Number, ISSN, or LCCN." Library Resources and Technical Services 37 (4): 403-13.
• Caswell, Jerry V. 1995. "Importance and Use of Holding Links between Citation Databases and Online Catalogs." Journal of Academic Librarianship 21 (2): 92-96.
• Hakala, Juha. 2002. "Linking Articles and Bibliographic Records with Uniform Resource Names." The Serials Librarian 41 (3/4): 193-199.
• ISSN International Centre. ISSN Manual. Cataloguing Part. Paris: ISSN International Centre, 2003.
• Koltay, Emery.2003. "Ready Reference. How To Obtain an ISBN; How To Obtain an ISSN; How To Obtain an SAN." Bowker Annual Library and Book Trade Almanac 48: 555-64.
• National Library of Canada. ISSN: International Standard Serial Number. National Library of Canada, 1980.
• Reynolds, Regina. 2003. "ISSN." Cataloging & Classification Quarterly. 36 (3): 155.