A few years ago I created a command (key binding) reference document for the joe text editor under Linux. I have created this in Lyx / LaTeX so there is a nice 3 column, 2 page pdf which I hope to make available shortly.
I have now updated this to Joe 3.7
joe command reference – for joe 3.7 (2008)
Reference card By Paul Sutton : 14th May 2013
web : http://www.zleap.net
You can now download this from github