P. Van and W. Muschik
Structure of variational principles in nonequilibrium
thermodynamics
Phys. Rev. E 52, 1995, 3584-3590
There are a lot of different methods to construct variational
principles in physics. In this paper we investigate and classify some
of the known methods, focusing our treatment mainly on the variational
principles in non-equilibrium thermodynamics. This area of physics is
remarkably rich in different variational methods, because here we
cannot obtain a classical Hamiltonian variational principle for the
transport equtions, as far as if w consider them in their general form
and with their original variables.