.TILMedia.BaseClasses.PartialGasFunctions.densityDerivativeWRTpressure_phxi .TILMedia.BaseClasses.PartialGasFunctions.densityDerivativeWRTpressure_phxipartial function densityDerivativeWRTpressure_phxi = TILMedia.BaseClasses.PartialGasFunctionPrototypes.densityDerivativeWRTpressure_phxi;