Clarify what I've learnt of the history

It's quite a mess, but these links might clear stuff up for someone who
wants to know more.

1 files changed, 10 insertions, 3 deletions

diff --git a/history.markdown b/history.markdown
index 1a7a659..832258f 100644
--- a/history.markdown
+++ b/history.markdown
@@ -1,11 +1,18 @@
 This program is based Jon A. Maxwell "JAM" `jmaxwell@acm.vt.edu` 's discovery
-that X11 keyboard state can be logged without superuser permissions.
+and proof-of-concept that X11 keyboard state can be logged without superuser
+permissions. (I'm not aware of others prior.)
 
 His program `xspy` is an X11 keylogger which output is squarely aimed at
 human-readability, which makes it great for (as the name suggests) spying on
-someone and quickly making out what they're doing. It has hence been included
-in security-focused Linux distributions (BackTrack and BlackArch, at least).
+someone and quickly making out what they're doing. Close variations of it have
+hence featured in security-focused Linux distributions ([in Kali][1] and [in
+BlackArch][2], [among others][3]).
 
 This is a complete rework of his idea, using a modern C version and with the
 aim of producing machine-readable output better suitable for physical key press
 statistics, deprioritising human parseability of the output.
+
+
+[1]: http://www6.frugalware.org/mirrors/linux/kali/kali/pool/main/x/xspy/
+[2]: https://github.com/BlackArch/blackarch/blob/master/packages/xspy/PKGBUILD
+[3]: http://www.freshports.org/security/xspy/)