“…Indeed, in the work of [1] coefficients were reported for ethylene, benzene and toluene, which are fluids that Kunz et al [4] reported to be further incorporated into the GERG-2004 equation. On the other hand, and more importantly, it was shown in [2] that the mixture model meets the requirements on accuracy of the current multi-fluid mixture models [9]. Therefore, those promising results support the hypothesis that the mixture model would meet the required accuracy for natural gases and related systems.…”