This article presents a procedure for formulation for the thermodynamic properties of pure substances using two primary sets of data, namely, the pvT data and the specific heat data, such as the constant pressure specific heat c(p) as a function of pressure and temperature. The method makes use of a linkage, on the basis of the laws of thermodynamics, between the virial coefficients for the pvT data correlation and those for the corresponding specific heat data correlation for the substance. The resulting equations of state take on remarkably simple analytic forms that give accurate predictions over the range of input data employed.