Estimation of regurgitant volume and orifice in aortic regurgitation combining CW Doppler and parameter estimation in a Windkessel-like model. - Bjørn A. J. Angelsen; Stig A. Slordahl; Jan Erik Solbakken; Stein O. Samstad; David T. Linker; Hans Torp; Hroar Piene (IEEE Trans. Biomed. Eng., 1990)