NLM® uses XML for MEDLINE® Data When the National Library of
Medicine endeavored to modernize its computer systems in the
late 1990s/early 2000s, the NLM chose XML (eXtensible Markup
Language) as the new tagged format for disseminating its MEDLINE
bibliographic citation data. A DTD (Document Type Definition)
defines the structure of this XML. This is the only distribution
format for MEDLINE data created beginning with the 2001
production year. The suite of DTDs used for MEDLINE/PubMed data
are available at http://www.nlm.nih.gov/databases/dtd/. This
decision strengthens NLM's commitment to distribute its journal
citation data in a format that is widely described and,
therefore, familiar to many in the information industry,
especially in the Internet Web environment. XML lends itself to
human readability as well as to easy machine manipulation. In
its transition to XML, NLM took the opportunity to examine the
MEDLINE unit record and make organizational data changes such as
moving information that enhances the