Godunov-type approximation for a general resonant balance law with large data

We consider the Cauchy problem for the 2 x 2 nonstrictly hyperbolic system [...] For possiblylarge, discontinuous and resonant data, the generalized solution to the Riemann problem is introduced, interaction estimates are carried out using an original change of variables and the convergence of Godunov approximations is shown. Uniqueness is addressed relying on a suitable extension of Kruz?kov's techniques