David Sewell schreef:
>    My <seg type="keyword" xml:id="kw1" corresp="#kwref1">last Letter</seg> was ...
> 
> and
> 
>    Short's <ref type="keyword" xml:id="kwref1" corresp="#kw1" rend="sc">last
>    letter</ref> was that of 26 Mch;

I think this is a sensible approach.

Just to simply a little, I think for the markup you don't need the link 
from text to note; an application can create the reverse link as needed. 
Simlarly, the rend="sc" would seem superfluous: what the source 
expresses by using small caps, the electronic version expresses by using 
a ref (or q) element.

(If you still want to capture the small caps you might also use the 
rendition element in the header)

Peter