Acoustic Determination of Thermophysical Properties and Critical Parameters for the Mixture (51 wt % R143a + 49 wt % R125) and Critical Line of xCO2 + (1-x)(51 wt % R143a + 49 wt % R125) Esperança, J.M.S.S.; Pires, P.F.; Guedes, H.J.R.; Ribeiro, N.; Costa, T.; Aguiar-Ricardo, A.; Journal of Chemical & Engineering Data 2006, 51, 2161-2169