Documentation for Authors

Introduction to <article>

In the Authoring Tag Set, the topmost element (your XML “document”) is an <article>. An article is a top-level component of a journal, for example, a research article, an editorial, or a book review.

Each article is composed of one or more parts which must appear (if present) in the following order:

How to Read This Tag Library

Terms and Definitions


Elements are nouns, like “Speech” and “Speaker”, that represent components of journal articles, the articles themselves, and accompanying metadata.


Metadata is data about the data, for example, bibliographic information. The distinction is between metadata elements which describe an article (such as the copyright year for the article) versus elements which contain the textual and graphical content of the article (such as a paragraph or a list).


Attributes are name/value pairs that hold facts about an element, for example, 1) the name of a pointer to an external file that contains an image, 2) a unique identifier, so that an element may be referenced, or 3) an indication of which type of list (e.g., numbered, bulleted, or plain) is being requested when using the <list> tag. Each attribute has both a name (e.g., list-type ) and a value (e.g., “bulleted”).

How To Start Using This Tag Library

The NLM Authoring Tag Set is available on the NLM Journal Archiving and Interchange Tag Suite website including: the Tag Set models expressed as DTDs, XSD schemas, and RELAX NG schemas; one or more tagged sample documents; and this Tag Library documentation (a set of linked HTML files). The DTD file delivery includes the Authoring DTD, the DTD customization files needed for Authoring to over-ride the declarations in the NLM modular Suite, and the modules that comprise the full Suite.

How you use the documentation will depend on what you need to learn about the modules and the Tag Set.

Learn the Tag Set

If you want to learn about the elements and the attributes in this Tag Set, so that you can write an article using the tag set, edit an article that is already tagged in this tag set, or learn how the journal article model is constructed, here is a good way to start.

  • Read the Tag Library General Introduction, taking particular note of the next section which describes the parts of the Tag Library, so you will know what resources are available.
  • Next, if you do not already know the symbols used in the Document Hierarchy diagrams, read the “Key to the Near & Far® Diagrams”.
  • Then (once you know the symbols), scan the Document Hierarchy diagrams to get a good sense of the top-level elements and their contents. (Find what is inside an <article>, then look at what is inside each of the large pieces of an article (such as body and front matter). Look at body first, then metadata, then keep working your way down.)
  • Pick an element from one of the hierarchy diagrams. Look up that element in the Elements Section to find the full name of the element, its definition, usage notes, content allowed, and any attributes. Look up or link to one of the attributes to find its full name, usage notes, and potential values.).

Tag Library Organization

This Tag Library contains the following sections:


This introduction to the contents of this Tag Library, to the design philosophy and intended usage of the Archiving and Interchange Suite, and to the Authoring Tag Set

Elements Section

Definitions, tagged examples, and usage notes for each of the elements in the Authoring Tag Set (and the parts of the Archiving and Interchange Suite used in this Tag Set). The element descriptions are listed in alphabetical order by tag name.

(Note: Each element has two names: a “tag name” (formally called an element-type name) that is used in tagged documents, in the DTDs/schemas, and by XML software, and an “element name” (usually longer) that provides a fuller, more descriptive name for the benefit of human readers. For example, a tag name might be <disp-quote> with the corresponding element name Quote, Displayed or a tag name might be <verse-group> with the corresponding element name Verse Form for Poetry.

Attributes Section

Descriptions of the attributes in the Article Authoring Tag Set.

Like elements, attributes also have two names: the shorter machine-readable one and a (usually longer) human-readable one. Attributes are listed in order by the shorter machine-readable names, for example, the attribute short name list-type instead of the more informal, easier to read: Type of List.

Parameter Entity Section (For Implementors Only)

Names (with occasional descriptions) and contents of the Parameter Entities in the DTD modules

Context Table

Listings of where each element may be used. All elements in the Tag Set are given in a simple alphabetical list.

The Context Table is formatted in two columns. The first column lists an element’s tag name as well as its descriptive name, and the second column lists the tag and name pairs of all the elements in which the listed element may occur. For example, if the first column contains the front matter element <front> and the second column contains only the article element <article>, this means that the <front> (Front Matter) element may only be used inside an <article> (Article) element.

Most elements may be used inside more than one other element. For example, the element <access-date> (Access Date for Cited Work) may be used inside the <citation>, <nlm-citation>, <product>, and <related-article> elements.

Note: These Context Table listings (which list where an element may be used) are the inverse of the content definition that is given as a part of each element description, which lists what can be inside the named element.

Document Hierarchy Diagrams

Tree-like graphical representations of the content of many elements. This can be a fast visual way to determine the structure of an article or of most elements within an article.

Authoring and Suite Naming Rules

The naming conventions for element and attribute names, such as the use of lower case, concatenation, and abbreviations within tags

Full Article Sample

A complete article is provided in XML according to this Tag Set. This sample has been provided to help users better understand the Tag Set’s overall structure and the relationship between elements.

DTD Section

Reference copies of the Authoring DTD, its five DTD-specific customization modules, and the modules of the full Archiving and Interchange Suite.

Index By Element Name

Index of element descriptions, alphabetically by element name (the longer, more descriptive name)

Index By Tag Name

Index of element descriptions, alphabetically by tag name (element-type name)

Typographic Conventions

<alt-text> The tag name of an element (Written in lower case with the entire name surrounded by “< >”)
Alternate Title Text (For a Figure, Etc.) The element name (long descriptive name of an element) or the descriptive name of an attribute (Written in title case, that is, with important words capitalized, and the words separated by spaces)
must not Emphasis to stress a point