Per Arvid Steen

Regional myocardial long-axis strain and strain rate measured by different tissue Doppler and speckle tracking echocardiography methods: a comparison with tagged magnetic resonance imaging.

Jonas Crosby, Hans Torp, Asbjørn Støylen, 2009, European journal of echocardiography : the journal of the Working Group on Echocardiography of the European Society of Cardiology.

Real-time simultaneous triplane contrast echocardiography gives rapid, accurate, and reproducible assessment of left ventricular volumes and ejection fraction: a comparison with magnetic resonance imaging.

Sigmund Frigstad, S. Frigstad, P. A. Steen, 2006, Journal of the American Society of Echocardiography : official publication of the American Society of Echocardiography.