<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).

Remarks

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>”.
A <label> can be used to preserve the prefix number for a reference or citation “25.” or “[Lapeyre 2010]”. This can be useful when reconstructing untagged cross-references.
Accessibility: 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, the element figure that follows might be pronounced as “Figure 3”.
<label alt="figure 3">Fig&#x00A0;III.</label>

Attributes

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 | serif | strike | underline | underline-start | underline-end | ruby | alternatives | inline-graphic | 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)*

Description

This element may be contained in:

Example 1

For a table:
...
<table-wrap id="t2" orientation="portrait" position="float">
<label>Table II.</label>
<caption>
<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>
</caption>
<table border="1">...</table>
</table-wrap>
...
    ...
<table-wrap id="pbio-0020328-t002" position="float">
<label>Table 2</label>
<caption>
<title>Genes Activated in the Mother-Cell Line of Gene Expression</title>
</caption>
<alternatives>
<graphic xlink:href="pbio.0020328.t002.tif"/>
<table frame="box" rules="all" cellpadding="5">...</table>
<supplementary-material id="S1" xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:title="local_file" xlink:href="pbio-0020328-t002.xls"
mimetype="application/vnd.ms-excel">
<label>Supporting Material</label>
<caption>
<p>Supplementary Microsoft Excel file (raw study data) supplied by authors.</p>
</caption>
</supplementary-material>
</alternatives>
<table-wrap-foot>...</table-wrap-foot>
</table-wrap>
...   

Example 2

For a figure:
    ...
<sec id="bid.36">
<title>Microbial Genomes</title>
<p>... A CON entry, containing instructions on how to put
the pieces back together, is also made. The CON entry
contains descriptor information, such as source organism
and references, as well as a join statement providing
explicit instructions on how to generate the complete
genome from the pieces. The Accession number assigned 
to the CON record is also added as a secondary Accession
number on each of the pieces that make up the complete
genome (see <xref ref-type="fig" rid="bid.37">Figure 2</xref>).
<fig id="bid.37">
<label>2</label>
<caption>
<title>A GenBank CON entry for a complete bacterial 
genome.</title>
<p>The information toward the <italic>bottom</italic> of the 
record describes how to generate the complete genome
from the pieces.</p>
</caption>
<graphic xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:href="ch1f2" mime-subtype="gif"/>
</fig>
</p>
...</sec>
...   
 ... 
<fig id="f3" position="float">
<label>FIG. 3.</label>
<caption>...</caption>
<alternatives>
<graphic specific-use="print" xlink:href="1.4821168.figures.highres.f3.zip"/>
<graphic specific-use="online" xlink:href="1.4821168.figures.online.f3.jpg"/>
</alternatives>
</fig>
... 

Example 3

In a note:
...
<ref id="c35">
<label>35.</label>
<note>
<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>
</note>
</ref>
...

Example 4

In an element-style bibliographic reference (punctuation and spacing removed):
...
<ref-list>...
<ref id="B8">
<label>8</label>
<element-citation>
<person-group person-group-type="author">
<name><surname>Weissert</surname>
<given-names>W</given-names></name>
<name><surname>Livieratos</surname>
<given-names>B</given-names></name>
</person-group>
<article-title>Effects and costs of day-care
services for the chronically ill: a randomized
experiment</article-title>
<source>Medical Care</source>
<year iso-8601-date="1980">1980</year>
<volume>18</volume>
<fpage>567</fpage>
<lpage>584</lpage>
<pub-id pub-id-type="publisher-id">WES-6772889</pub-id>
</element-citation>
</ref>
...</ref-list>
...

Example 5

In a mixed-style bibliographic reference (punctuation and spacing preserved):
...
<ref-list>...
<ref id="B8">
<label>8</label>
<mixed-citation publication-type="journal" publication-format="print">
<string-name><surname>Weissert</surname>,
<given-names>W</given-names></string-name>,
<string-name><surname>Livieratos</surname>,
<given-names>B</given-names>
</string-name>.
<article-title>Effects and costs of day-care
services for the chronically ill: a randomized
experiment</article-title>. <source>Medical Care</source>
<year iso-8601-date="1980">1980</year>;<volume>18</volume>:
<fpage>567</fpage>&ndash;<lpage>584</lpage>.
<pub-id pub-id-type="publisher-id">WES-6772889</pub-id>.
</mixed-citation>
</ref>
...</ref-list>
...

Example 6

For a hypothesis:
...
<sec>...
<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:
<statement>
<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>
</statement>
</p>
</sec>
...