This article, in the proceedings of the Fifth Australian Space Science Conference in 2005, isn't terribly accessible - but for those of you who are interested, it is now available on my Flinders University website. This is the URL:
http://ehlt.flinders.edu.au/archaeology/staff/gorman.php
There is an icon next to the article to click.
Update 22 January 2015: broken link - the new link is here.