A review of the state of play was published in 2007, as a Supplement to NICS, and can downloaded from: [url]http://www.unscn.org/en/publications/nics/index.php#Supplements[/url] The HTP v2 also has a module on this and links to other training resources: [url]http://www.ennonline.net/htpversion2/modules[/url] Hope these help a bit.