Relativistic mechanical-thermodynamical formalism -- description of   inelastic collisions
  We present a relativistic formalism inspired on the Minkowski four-vectors that also includes conservation laws such as the first law of thermodynamics. It remains close to the relativistic four-vector formalism developed for a single particle, but it is also related to the classical treatment of problems that imperatively require both the Newton's second law and the energy conservation law. We apply the developed formalism to inelastic collisions to better show how it works. 
Julio Guemez, Manuel Fiolhais, Luis A. Fernandez
physics.class-ph