1. J. H. Keenan, Thermodynamics, John Wiley & Sons, New York (1941).
2. M. Planck, Treatise on Thermodynamics, Longmans and Green, New York (1927), pp. 40–47.
3. J. W. Gibbs, Collected Works, Vol. 1, Longmans and Green, New York (1931), p. 51.
4. H. C. Weber, Thermodynamics for Chemical Engineers, John Wiley & Sons, New York (1939).
5. S. Carnot, Reflections on the Motive Power of Fire, Manchester Univ. Press, Manchester (1986).