Improved Characterization of Non-Stationary Flows Using a Regularized Spectral Analysis of Ultrasound Doppler Signals A. Herment, J.-F. Giovannelli, G. Demoment, B. Diebold and A. Delouche J. Phys. III France, 7 10 (1997) 2079-2102 DOI: 10.1051/jp3:1997242