XPointer
<!DOCTYPE SPEECH [
<!ELEMENT SPEECH (#PCDATA|SPEAKER|DIRECTION)*>
<!ATTLIST SPEECH
ID ID #IMPLIED>
<!ELEMENT SPEAKER (#PCDATA)>
<!ELEMENT DIRECTION (#PCDATA)>
]>
<SPEECH ID="a27"><SPEAKER>Polonius</SPEAKER>
<DIRECTION>crossing downstage</DIRECTION>Fare you well,
my lord. <DIRECTION>To Ros.</DIRECTION>
You go to seek Lord Hamlet? There he is.</SPEECH>
id(a27).child(2,DIRECTION)
id(a27).child(2,#element)
id(a27).child(2,#text)