Introduction to DOI

What is a DOI?

A Digital Object Identifier (DOI) is a permanent, unique identifier assigned to digital objects such as research articles, datasets, books, or reports. Unlike URLs, which may break over time, DOIs ensure persistent access to digital content even if its location changes. DOIs are standardized through the International DOI Foundation and are widely used in academic publishing to reliably link and cite scholarly materials.

DOIs also provide metadata about the object, including authorship, publication details, and licensing information. Publishers, repositories, and institutions often assign DOIs to materials to enhance discoverability and support proper citation practices.

What does a DOI look like?

A DOI typically follows this format:
10.XXXX/XXXXXX
Examples include:

• 10.1038/378355a0
• 10.1103/PhysRevLett.58.2059

DOIs consist of two parts:

1. Prefix: Begins with 10. followed by a unique number (e.g., 10.1038).
2. Suffix: Assigned by the publisher or repository (e.g., 378355a0 or PhysRevLett.58.2059).

DOIs may appear as:

• Full URL: https://doi.org/10.XXXX/XXXXXX
• Shortened form: doi:10.XXXX/XXXXXX

Where Can I Find the DOI?

DOIs are commonly located in these places:

1. Journal articles:
   • On the first page, near the title or author names.
   
   • In the article’s header/footer or citation/references section.
   
2. Databases and platforms:
   • In search results or metadata records (e.g., PubMed, CrossRef, or publisher websites like Elsevier).
3. PDF documents:
   • In the top/bottom margins or under “Article Info.”
4. Books or reports:
   • On the copyright page or in the publication’s metadata.

If a DOI is unavailable:

• Check the publisher’s website or use tools like CrossRef to search by title/author.
• Some articles published prior to 1998 are less likely to have DOIs. or non-academic materials may lack DOIs.