I agree with Brian, if you can put in a "placeholder" link and encode it 
in such a way that the link isn't likely to break, then this is the best 
of all possible solutions.  You can have the stylesheet test whether the 
file you are linking to exists before generating a link - either on the 
fly or if you pre-process you EAD files like we do.  We are doing 
something similar in a legacy finding aid conversion project. 
Eventually we'll be linking to a PDF version of the legacy 
inventory/container list, but those haven't been created yet.  However, 
I created a "stub" in the EAD file so that once those files are created, 
the links to these files will automagically become activated.  This sure 
beats going back into ca. 3,500 files and inserting those links manually!

Also, as Mary L. already pointed out, if you're linking to archival 
collections, <archref> is technically the correct linking element.

Mark Carlson
Computer Support Analyst
Special Collections Division
University of Washington Libraries
BOX 352900
Seattle, WA, 98195
(206) 543-1929
http://staff.washington.edu/carlsonm/


Michele Combs wrote:
> I'm curious about implementations of the EAD <relatedmaterial> element
> (cross-posted to both EAD and Archives and Archivists listservs):
> 
> 1) If you are routinely using this to point users to related
> collections, are you making these items links or plain text?
> 
> 2) If you are making them links (extrefs), are you a) inserting the
> link at the time of tagging, even if the target related finding aid is
> not yet done, or b) leaving it plain text and going back later to insert
> the link when the target related finding aid is done?  
> 
> 2a) If the former, for related finding aids that are not yet in EAD are
> you linking to a temporary target (for example to a placeholder "This
> finding aid is not yet electronic" message) or are you putting in the
> correct href for the future finding aid (thus creating a temporarily
> dead link)?
> 
> 2b) If the latter, how are you tracking them so you know to go back
> later and insert the link?
> 
> Thanks -
> 
> Michele C.
> 
> 
> 
> 
> -=|=--=|=---=|=---=|=---=|=---=|=---=|=---=|=--
> Michele R. Combs
> Librarian for Manuscripts and Archives Processing
> Special Collections Research Center
> Syracuse University Library
> 222 Waverly Avenue
> Syracuse, NY 13244
> (315) 443-9758
> -=|=--=|=---=|=---=|=---=|=---=|=---=|=---=|=--