---
type: Changelog Entry
title: Several ISBNs, DOIs, PMIDs and other identifiers per publication
resource: https://www.librario.de/en/changelog/2026-03-multiple-identifiers
language: en
revision: e114aa541d24c57e452957a2313c85d2014b716b
tags:
- changelog
---

# Several ISBNs, DOIs, PMIDs and other identifiers per publication

A publication could previously carry only one ISBN, one DOI, one PMID and so on.



In practice many publications have several, such as a hardcover and a softcover ISBN, or a print and an online DOI. Librarians had to settle on one variant or squeeze the second ID into a notes field, where it was lost to search and export.



Every publication can now carry any number of identifiers as an ordered list: ISBNs, DOIs, PMIDs, arXiv IDs, ISSNs and custom identifier types. Set the order by drag and drop. Search, CSV export and the API take every value into account; BibTeX and EndNote contain the first ISBN, DOI, ISSN and PMID.