Comparison of cardiac output measurement techniques: thermodilution, Doppler, CO2-rebreathing and the direct Fick method. - Espersen,K.; Jensen,E.W.; Rosenborg,D.; Thomsen,J.K.; Elliasen,K.; Olsen,N.V.; Kanstrup,I.L. (Acta Anaesthesirol Scand, 1995)