MyST Markdown

# Cross-references

References refer to labeled content (e.g. a figure, document or table) and automatically generates links and extra information, like numbering. This page covers the basics of setting up references to content and shows examples for sections, figures, tables and equations.

## #1Directive Targets

Targets are custom anchors that you can refer to elsewhere, for example, a figure, section, table, program, or proof. To be referenceable, they must have a label/identifier pair in the AST. These can be created by setting the label option in many directives. For example, to label and reference a figure, use the following syntax:

Cross-referencing content is accomplished with markdown link syntax ([text](#target)) where #target is the target label, like the figure, equation or section header that you are referencing. If you leave the text empty, MyST will fill in the link with the title, caption, document name, or equation number as appropriate (e.g. "Figure 1" or "Section 1.3.7"). If you do supply text, you can control what is displayed in the reference, as well as have access to placing the name and enumerator of the target, using {name} and {number}, respectively.

MyST SyntaxRendered
[](#targeting-headers)
Default for numbered references is to fill in the listing and number (e.g. Figure 1.).
Note that headings are numbered on this page, so it will show the number rather than the header title.
[Sec. %s](#targeting-headers)
Modify the title, but keep the enumerator, you can use {number} or %s to place the number.
Note that unnumbered targets (e.g. a paragraph) will resolve the number to ??, similar to $\LaTeX$, and a warning shown.
[Sec. **_%s_**](#targeting-headers)
Markup is parsed first and then the content in placed.
Content inside of inlineCode is not replaced.
[Section "{name}"](#targeting-headers)
Use {name} to place the name of the header in the content.
Headers resolve the text of the header, if there is a caption in the target it will be used.
For targets that do not have a caption or header, the name will resolve to the label.
[**bold _reference_**](#targeting-headers)
If you override the text in the link, that will be used.
[](./citations.md)
Link to documents using relative links from the markdown.
[](./_toc.yml)
Link to static files that will be included in your built website.
_toc.yml

## #3Header Targets

To add labels to a header use (my-section)= before the header, these can then be used in markdown links and {ref} roles. This is helpful if you want to quickly insert links to other parts of your book. Referencing a heading will show the heading and the subsequent two pieces of content, unless a header is encountered.

## #4Header Numbering

By default section numbering for headers is turned off with numbering for figure and table numbering enabled. To turn on numbering for headers, you can can change the frontmatter in the document or project.

## #5Equations Targets

To reference equations, use the {eq} role. It will automatically insert the number of the equation. Note that you cannot modify the text of equation links.

## #6Label Anything

It is possible to label any document node by adding (my-label)= before any other block of content. These can be referenced using the {ref} role, but by default will not be enumerated, so you cannot use %s or {number} in the content.

## #7Referencing using Roles

ref
The {ref} role can be used to bring the title or caption directly in line, the role can take a single argument which is the label, for example, {ref}reference-target
You can also choose the reference text directly (not taking from the title or caption) by using, {ref}your text here <reference-target>.
numref
The {numref} role is exactly the same as the above {ref} role, but also allows you to use a %s in place of the number, which will get filled in when the content is rendered. For example, {numref}Custom Table %s text <my-table-ref>. will become Custom Table 3 text.
eq
The {eq}my-equation syntax creates a numbered link to the equation, which is equivalent to [](#my-equation) as there is no text content to fill in a title or caption.
doc
The {doc}./my-file.md syntax creates a link to the document, which is equivalent to [](./my-file.md).
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