base function for region 5: g(p,T), including 3rd derivatives
function g5L3 extends Modelica.Icons.Function; input Units.SI.Pressure p "pressure"; input Units.SI.Temperature T "temperature (K)"; output ThermoSysPro.Properties.WaterSteam.Common.GibbsDerivs3rd g "dimensionless Gibbs funcion and dervatives wrt pi and tau"; end g5L3;