<label> Label (of an Equation, Figure, Reference, etc.)

Number and/or prefix word placed at the beginning of display elements (for example, equation, statement, figure).


As an example, a label placed at the beginning of an equation (<disp-formula>) could be a number such as <label>Equation 3.</label>, <label>(3)</label>, or <label>3.</label>. A label before a statement, such as a Proof or Lemma, could be a word such as <label>Proof</label> or <label>Hypothesis</label>.
Many objects can take explicit labels. For example, a <label> can contain the number or symbol used as a prefix character for a footnote that is placed at the point of the footnote reference. Similarly, the number and any prefix word associated with the title or the caption of a <fig> can be marked as a <label>, for example, “<label>Figure 3.</label>”, “<label>Exhibit 2.</label>”, or “<label>3.</label>”.
In citations, a <label> can be used to preserve the prefix number for the reference or citation, for example, “25.” or “[Richardson 2010]”. This can be useful when reconstructing untagged cross-references.
Sometimes a <label> needs to be pronounced in a way that is not reflected in its content or its tagging. The @alt attribute can be used to record the pronunciation for screen readers and other accessibility devices. For example, a cross-reference to a figure might be pronounced as “Figure 3”.
<label alt="figure 3">Fig&#x00A0;III.</label>

Base Attributes

Models and Context
May be contained in
Any combination of:
Content Model
<!ELEMENT  label        (#PCDATA %label-elements;)*                  >
Expanded Content Model

(#PCDATA | email | ext-link | uri | inline-supplementary-material | related-article | related-object | hr | bold | fixed-case | italic | monospace | overline | overline-start | overline-end | roman | sans-serif | sc | strike | underline | underline-start | underline-end | ruby | alternatives | inline-graphic | inline-media | private-char | chem-struct | inline-formula | tex-math | mml:math | abbrev | index-term | index-term-range-end | milestone-end | milestone-start | named-content | styled-content | fn | target | xref | sub | sup | x | break)*

Tagged Samples
<table-wrap id="t2" orientation="portrait" position="float">
 <label>Table II.</label>
  <p>Models to approximate the bound frequencies as waves 
   in X→M (<inline-graphic id="g1" xlink:href="d1"/>: Rotational, 
   <inline-graphic id="g2" xlink:href="d2"/>: Vibrate in <italic>y</italic> 
   direction, <inline-graphic id="g3" xlink:href="d3"/>: Vibrate in
   <italic>x</italic> direction, <inline-graphic id="g4" xlink:href="d4"/>: 
   Vibrate mainly in <italic>y</italic> direction including a small 
   portion of vibration in <italic>x</italic> direction, 
   <inline-graphic id="g5" xlink:href="d5"/>: Vibrate mainly in 
   <italic>x</italic> direction including a small portion of vibration 
   in <italic>y</italic> direction).</p>
 <table border="1">...</table>
 <title>Outcome data</title>
 <p>Figure <xref ref-type="fig" rid="F2">2</xref> shows that
  overall there was no significant difference between day hospital
  and alternative forms ...</p>
 <fig id="F2">
  <label>Figure 2</label>
  <caption><p>Odds of death or poor outcome in patients
   receiving day hospital care or alternative services (random
   effects model). Heterogeneity between trials is presented
   as &#x03C7;<sup>2</sup></p></caption>
  <graphic xmlns:xlink="http://www.w3.org/1999/xlink"
<fig id="f3" position="float">
 <label>FIG. 3.</label>
  <graphic specific-use="print" xlink:href="1.4821168.figures.highres.f3.zip"/>
  <graphic specific-use="online" xlink:href="1.4821168.figures.online.f3.jpg"/>
<ref id="c35">
  <p>The geometric optimization and electronic transport properties are 
   all calculated by a developed <italic>ab-initio</italic> software package 
   Atomistix ToolKit, which is based on the spin-polarized density-functional 
   theory combined with the non-equilibrium Greens functions. ...</p>
In citations
Mixed citation
<ref id="B1">
 <mixed-citation publication-type="book">
  <collab>Research Unit of the Royal College of 
  Physicians and British Geriatric Society</collab>. 
  <source>Geriatric day hospitals: their role 
  and guidelines for good practice</source>. 
  <year iso-8601-date="1994">1994</year>.
Element citation
<ref id="B8">
 <element-citation publication-type="journal">
  <person-group person-group-type="author">
  <article-title>Effects and costs of day-care
   services for the chronically ill: a randomized
  <source>Medical Care</source>
  <year iso-8601-date="1980">1980</year>
  <pub-id pub-id-type="pmid">6772889</pub-id>
Hypothesis in <statement>
<article dtd-version="1.3">
  <p>Industrial buyers categorise foreign countries
   according to their level of technological achievement
   and subsequently differentiate their perceptions of
   these countries accordingly. ... The following
   hypothesis is posited:
    <label>Hypothesis 1</label>
    <p>Buyer preferences for companies are influenced 
     by factors extrinsic to the firm attributable to, 
     and determined by, country-of-origin effects.</p>
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