att.source

att.source provides attributes for pointing to the source of a bibliographic reference. [3.3.3 Quotation 8.3.4 Writing]
Moduletei — The TEI Infrastructure
Membersatt.responsibility [att.editLike [att.transcriptional [add addSpan del delSpan mod redo restore retrace subst substJoin undo] affiliation age am birth climate corr date death education event ex expan faith floruit gap geogFeat geogName langKnowledge langKnown location name nationality occupation offset org orgName origDate origPlace origin persName person place placeName population reg relation residence sex socecStatus state supplied surplus terrain time trait unclear] att.interpLike [interp interpGrp span spanGrp] att.textCritical [lem rdg rdgGrp] abbr abstract handShift note orig provenance respons rs seg sic witDetail] egXML q quote writing
AttributesAttributes
sourceprovides a pointer to the bibliographical source from which a quotation or citation is drawn.
Status Optional
Datatype 1–∞ occurrences of 

<rng:ref name="data.pointer"/>
data.pointer
separated by whitespace
Example
<p>
<!-- ... -->
As Willard McCarty (<bibl xml:id="mcc_2012">2012, p.2</bibl>)
tells us, <quote source="#mcc_2012">‘Collaboration’ is a
   problematic and should be a contested term.</quote>
<!-- ... -->
</p>
Example
<p>
<!-- ... -->
 <quote source="#chicago_15_ed">Grammatical theories
   are in flux, and the more we learn, the less we
   seem to know.</quote>
<!-- ... -->
</p>
<!-- ... -->
<bibl xml:id="chicago_15_ed">
 <title level="m">The Chicago Manual of Style</title>,
<edition>15th edition</edition>.
<pubPlace>Chicago</pubPlace>:
<publisher>University of Chicago Press</publisher>
(<date>2003</date>),
<biblScope unit="page">p.147</biblScope>.

</bibl>