Asonov, Dmitri; Agrawal, Rakesh (2004), Keyboard Acoustic Emanations(PDF), IBM Almaden Research Center, archived from the original(PDF) on 2012-02-27, retrieved 2013-09-08
Asonov, Dmitri; Agrawal, Rakesh (2004), Keyboard Acoustic Emanations(PDF), IBM Almaden Research Center, archived from the original(PDF) on 2012-02-27, retrieved 2013-09-08