[OPEN-ILS-GENERAL] LOC Z39.50 Search and ISBN numbers

[evergreen at copelan.com]

I have been using the Z38.50 (voyager) search to import bib records into EG.  This is working well 
and saving a ton of typing :-) but I have noticed one point that seems a bit strange.  

Sometimes I don't find the exact ISBN number of a book.  I know that the copy is being loaded has 
been out for a while (since we acquired it several years ago).   

Example: 
The Da Vinci Code   paperback ISBN 0-385-51322-4  Publisher: Doubleday.  The search yields nothing 
for this ISBN 

When searching for Da Vinci  in the Title and Brown, Dan in the Author there are 2 found: 
ISBN 0385513755   Special Illustrated edition (my paperback has no pictures)
ISBN 0385504209    This is the hardcover edition.

Neither of these 2 seem to be correct for the paperback I have in hand.  My assumption so far has 
been that the Voyager search would find at lease all USA published books.  Is this incorrect?  

Thanks for any info.

RobertC