version references in documentation

[Tom Bullock]

Hi Yawar,

I am pulling together the pieces of my patch.  When I ran it thru 
"xmllint", I got these xml error messages that I hope you understand and 
can tell me what is my error:

1.  validity error: Element xref was declared EMPTY this one has content
<xref linkend="ch_oth_assets.xml">Chapter 16</xref> of this Guide.</para>
     [the message does identify the line number in error]

2.  gnucash-guide.xml:293: element xref: validity error : IDREF 
attribute linkend references an
     unknown ID "ch_oth_assets.xml"

I have listed ch_oth_assets.xml in gnucash-guide.xml both as <!ENTITY 
chapter16 SYSTEM "ch_oth_assets.xml"> (given on line 19)  and also as 
&chapter16; (given on line 284)

So why does the error mention line 293, which is after last line 292, 
past the end of </book> shown on line 292?

It seems to me I am not using the referencing method correctly.   But I 
wonder also about the
possibility that I may need to set a value in a symbolic parameter you 
have introduced.

I did include ch-oth-assets.xml in the directory "guide/C" where all the 
modules are that make up the guide.

TIA for  all help.

Tom