<ChapterNumber> (Chapter Number)

This element specifies the number or index of the chapter being referenced.
example: :
<b:BookTitle>Title</b:BookTitle> 
<b:Pages>23-65</b:Pages> 
<b:Comments>Comments</b:Comments> 
<b:ChapterNumber>6</b:ChapterNumber> 
<b:RefOrder>1</b:RefOrder>

The possible values for this element are defined by the ST_String255 simple type (§7.6.3.2).

Parent Elements

<Source>7.6.2.59)