UNDERSTANDING RESEARCH REFERENCE NUMBERS

Research papers often have reference numbers attached.

Here is some information regarding those reference numbers:

DOI = Digital Object Number - a number that facilitates easy location of a document or article on the internet. Simply enter this number in a search engine.

Numbers assigned by the National Library of Medicine:

PMID = PubMed Indexed Documents. Also known as PubMed reference numbers.

PMCID = PubMed Central Identifier. It identifies works published in free-to-access Pub Med Central. Where PMID numbers are automatically assigned, PMCID requires application to insure their compliance with public access policy.