Andrew Williams
http://www.bolton.ac.uk/staff/adw1/gp2x/index.html
Reiner Prokein
http://reinerstileset.4players.de/
Lordieth (on deviantart)
http://lordieth.deviantart.com/
acclivity (on freesound)
http://freesound.iua.upf.edu/samplesViewSingle.php?id=18074
http://www.bbc.co.uk/science/humanbody/sleep/sheep/