Description on Youtube:
Schoenberg's manuscript at this link:
https://sites.google.com/site/francescobellomi1960bis/download
or
http://www.schoenberg.at/
or
http://www.schoenberg.at/index.php?option=com_content&view=article&id=374&Itemid=585&lang=de
Andy Lee web: http://andy-lee.com/Andy_Lee_Web_Portal.html
and also:
http://pianosociety.com/cms/index.php?section=1597
