4.4.3. Digital object identifier (DOI)

The digital object identifier (DOI) is used for identifying a product in a digital environment and is designed to ensure the perenniality of hypertext links.

The digital object identifier (DOI) system is used for identifying a product in a digital environment and is designed to ensure the perenniality of hypertext links. It may be applied to:

• an entire publication,
• a photo,
• a table,
• a chapter etc.

Each DOI is unique and permanent. A document keeps the same DOI for its entire lifetime and, if ever the document is deleted, the DOI will not be reused.

The DOI number is composed of a prefix and a suffix, separated by a forward slash. It must be in the following format (preceded by the lower-case letters ‘doi’ followed by a colon, with no space):

In principle, the location of the DOI follows the same rules as the ISBN or ISSN.