ISBN, ISSN and DOI

ISBN – Acronym for International Standard Book Number, a unique identifier for books consisting of thirteen digits preceded by an alphabetical prefix and divided into distinct elements separated by hyphens: the group identifier (determined by national, geographical, linguistic and other considerations); the publisher identifier; the title identifier; and the check digit, which enables computer systems to verify the validity of the number and prevent transcription errors. Since January 2007, the ISBN has consisted of thirteen digits.

Originally developed for publishers, the ISBN was later adopted by libraries as a search key in union catalogues, and some automated systems also use it as a control number. An ISBN identifies a specific edition of a work published by a particular publisher and is assigned to every published book, including its various editions and formats. The same title issued in different editions or formats, such as paperback or hardback, will have a different ISBN. In the case of a multi-volume work, one ISBN is assigned to the complete set and additional ISBNs are assigned to each individual volume.

ISBNs are allocated by the relevant National ISBN Agency and are based on the ISO standard (ISO 2108 – Information and Documentation – International Standard Book Number (ISBN)). The system is designed to enable the rapid identification of publications, facilitate ordering and distribution, and promote dissemination through bibliographies, catalogues, publishers’ lists and catalogue records.

in Dicionário do livro : da escrita ao livro electrónico / Maria Isabel Faria, Maria da Graça Pericão. - [Coimbra] : Almedina, cop. 2008. - 1287 p. : il. ISBN 978-972-40-3499-7

In Portugal, the ISBN Agency operates through APEL - Associação Portuguesa de Editores e Livreiros.

ISSN – Acronym for International Standard Serial Number, the internationally recognised identifier for serial publications.

The ISSN is a numerical code that serves as a unique international identifier for each serial publication title. It consists of eight digits arranged in two groups of four, separated by a hyphen and preceded by the acronym ISSN. The last digit is a check digit; if its value is 10, it is represented by the letter X, except where the calculation results in no remainder, in which case the check digit is 0. Any change in the title of a serial publication requires the assignment of a new ISSN.

The ISSN, together with the key title, provides an unambiguous means of identifying a serial publication. Its structure is based on principles similar to those of the ISBN. However, while the ISBN identifies a specific edition of a book, the ISSN identifies the serial publication itself and changes only when the publication title changes. The ISSN should appear in the upper right-hand corner of the cover, on the title page, or on the page containing the publication details. In serial publications issued in other media formats, it should preferably appear within the document, such as on the opening or main page, or on external elements such as a disc or cassette label, packaging, or microfiche header.

The ISSN is assigned through the International Serials Data System (ISDS) and is based on the international standard ISO 3297. The International ISSN Centre is located in Paris and works in conjunction with national centres established in participating countries, which are authorised to assign ISSNs. For online publications, the ISSN assigned to the electronic version of a serial publication is issued by the national ISSN centre of the country in which the publication is published.

in Dicionário do livro : da escrita ao livro electrónico / Maria Isabel Faria, Maria da Graça Pericão. - [Coimbra] : Almedina, cop. 2008. - 1287 p. : il. ISBN 978-972-40-3499-7

In Portugal, ISSN assignment is a service provided by the National Library.

ISO 3297 revised in 2017.

DOI – Acronym for Digital Object Identifier, a unique alphanumeric identifier used to provide a permanent and reliable means of identifying a digital object on the Internet. It serves a purpose similar to that of the ISBN for books and the ISSN for serial publications, enabling the persistent identification and location of intellectual property in digital environments, regardless of its physical or online location.

Source: Dictionary of the Book: From Writing to the Electronic Book / Maria Isabel Faria, Maria da Graça Pericão. Coimbra: Almedina, 2008. 1287 p. ISBN 978-972-40-3499-7.