Identifiers

Identifiers are used to uniquely identify electronic documents (DOI), journals (ISSN) and books (ISBN), authors (ORCID iD), or institutions (ROR ID). PubMed Identifiers (PMID) are persistent identifiers in the database PubMed.

Perma.cc is a web archiving service that attempts to solve the problem of dead links by creating permanent links to archived websites.