Treatise on Thermodynamics. E-book. Formato PDF Peter Alexander   -  Forgotten Books, 2017  - 

Chapter XVIII. Extends the ordinary definition of entropy to a body or system in which the temperature or pressure, or both, are not the same throughout the body or system, and thus opens up a mode of dealing with intrinsically irreversible transforma tions the same as that followed when the transformations are reversible.