1. A preliminary report has been published in P. Kumar,Physica B 199–200, 409 (1994).
2. See for example A.B. Pippard,Elements of Classical Thermodynamics, Cambridge University Press (1966) or M. W. Zemansky and R. H. Dittman,Heat and Thermodynamics, McGraw Hill, New York (1981). Eq. (2) in the textbooks is sometimes referred to as Ehrenfest equation, along with the equivalent expression for a I order phase transition, also known as Clausius-Clepeynon equation.
3. R. Goodrich, D. Hall, and C. Grenier, unpublished (1994).
4. M. F. Hundley, J. D. Thompson, and G. M. Kwei,Solid State Com. 70, 1155 (1989). This paper also contains a discussion of an earlier measurement by J. E. Graebner, C. F. Schneemeyer, and J. K. Thomas,Phys. Rev. B 39, 9682 (1989).
5. F. Seidler, P. Böhm, H. Gens, W. Brannisch, E. Braun, W. Schelle, Z. Drzazga, N. Wild, B. Roden, H. Schmidt, D. Wohleben, I. Felner, and Y. Wolfus,Physica C 157, 375 (1989).