CPR artifact removal from human ECG using optimal multichannel filtering. - Sven Ole Aase; Trygve Eftestøl; John Håkon Husøy; Kjetil Sunde; Petter Andreas Steen (IEEE Trans. Biomed. Eng., 2000)

Temporal Evolution of nonlinear Dynamics in Ventricular Arrhythmia. - Michael Small; Dejin Yu; Robert G. Harrison; Richard H. Clayton; Trygve Eftestøl; Kjetil Sunde; Petter Andreas Steen (Int. J. Bifurc. Chaos, 2001)